A Singaporean’s Guide to Using a Japanese Onsen [Updated 2023]

Travel on 9 Aug, 2023

A Singaporean’s Guide to Using a Japanese Onsen [Updated 2023]

Is there an onsen in Singapore? I’m happy to report that the answer is yes!

Singapore may have its very own Sembawang Hot Spring Park, but you cannot call yourself a true-blue onsen lover if you haven’t been to the traditional ones in Japan. As for a conservative Singaporean like me, the idea of stripping off my clothes and bathing with a bunch of old Japanese ladies is honestly quite nerve-racking.

So to save the awkwardness and prepare you for what you will find lurking among the steam, I’ve created the ultimate guide to the Onsen for Singaporeans. From the changing colours of the water to a tutorial on how to whip up a delicious Onsen Tamago straight from your home, here’s everything you need to know about the traditional practice.

If you would like to know which onsens are Singaporeans’ favourite, check out Top 10 Best Onsens in Japan 2023: Voted by Singaporeans blog.

What is an Onsen?

Onsen (温泉) is a Japanese hot spring with many types, sizes, and shapes. As Japan is a volcanically active country, thousands of these pools are found around the island.

Back in the 12th century, bathing in onsen pools started due to the influence of Buddhism. Buddhists believe that by immersing one’s body in ‘divine’ waters, the bather will be cleansed of the sins of the flesh, and the goodwill of the deities will be, thus, conferred upon him or her.

It was only in the 17th century that people started recognizing the health benefits of the onsen, attracting travellers to the spring water.

Onsen Singapore - Rotenburo Outdoor Onsen at Ikeda Spa, Bukit Timah
Rotenburo Outdoor Onsen at Ikeda Spa, Bukit Timah

During the Winter Solstice, the Japanese will place tangy fruits such as yuzu in the water to ward off colds in the coming winter! They also add a citrusy and refreshing fragrance to enhance the entire experience.

Little to no doubt that onsens have always been an integral part of the Japanese’s lives. It has been ingrained in their culture to want only the best for their baths and take a good bath to end a busy day. They even relish going on onsen retreats to bathe, relax and bask in the feelings the calming water provides.

TL;DR: Onsen FAQs

How hot is an onsen?

It can vary, but the hottest baths are usually around 42 degrees Celsius. Some have much cooler baths. The Japanese hot spring law defines an onsen as water, water vapour or other gases that emerge from the earth at least 25 degrees Celsius or with a minimum concentration of certain minerals.

How much time do I need to visit an onsen?

You should spend at least an hour. When you’ve finished showering, having a quick soak in the bath, and changing again, the hour is almost up. If you want to take your bath longer, two hours is a comfortable time.

Is talking allowed in the onsen?

As long as you’re not talking too loudly, it’s fine to speak in the onsen. It’s quite common for people to go there with their friends or family members to talk in a relaxed setting. However, rowdiness is not acceptable. So please be mindful of everyone’s right to enjoy the facilities.

Can I wear a swimsuit to the onsen?

No, you must be naked inside the baths. Baths are usually sex-segregat­ed because of this. Some onsens have a joint area where men and women can enjoy soaking together. These areas are generally more like spas; sometimes, swimsuits are worn in this context. However, most onsen simply has separate areas for naked bathing.

Can I bring a camera?

For obvious reasons, you cannot take pictures inside the changing room or in the bathtubs. Some onsen may have stricter policies about the whole premises – just pay attention to signage or ask if you’re unsure. Most of the time, keeping the camera in your locker while using the facilities is fine.

Can babies/children go to the onsen?

Yes, of course. Young accompanied children may enter either bath with their guardian. Older children should go to the bath assigned for their gender. Note that the onsen you are visiting may have a policy on the minimum age a child must be to enter the baths unaccompanied.

I have a tattoo. Can I visit an onsen?

Tattoos, even if small and simply a means of artistic expression, are generally not allowed in onsen due to their association with the yakuza, or Japanese mafia. If your tattoo is not too big, you might be able to cover it up with a skin-coloured waterproof bandage. Do so beforehand, as you may be asked to leave if your body art is spotted upon entry or in the changing room. Check the policy of the onsens you’re visiting, but be prepared to be turned away.

I have my period. Can I use an onsen?

Unfortunately not. Since no swimsuits are allowed in the onsen, you can’t wear a tampon like you would at a beach or swimming pool. You might consider using a moon cup to skirt around this issue entirely.

How can I find an onsen on a map?

Onsens are indicated on maps and signs with the symbol ♨ or the character 湯 (yu, meaning hot water), sometimes expressed in the simpler hiragana text as ゆ so younger children can read it.

Onsen vs Sento: What’s The Difference?

Don’t get confused between the two! Though both are considered public baths, the Onsen and Sento serve different functions. Think of the onsen as nature’s pool for relaxation and the Sento as a man-made facility for self-cleaning.

In kanji, Sento (銭湯) translates into “coin” and “hot water”, respectively. And if you can already deduce from its name, the Sento is essentially a place where you can buy hot water to bathe or shower. Popular in the post-war era due to population increase and smaller houses to make up for it, many families turned to their local Sento to bathe as not all houses came equipped with washing facilities. 

It’s been recorded that more than 20,000 Sento existed in the mid-1960s, with only 5,000 left in Japan today. If you were to experience bathing in one of these traditional Sento today, you’d have to venture into residential areas. 

Before going to a Sento, prepare soap, shampoo, towels, and toiletries if you need them later. Once you’re there, make payment (about ¥460 for one adult in Tokyo) at the reception counter and proceed to the locker room to remove all your clothing. You may place your clothing into the lockers or lockboxes there.

After undressing, bring your small towel with you to the washing area. Before entering the shared bath, wash your entire body with hot water and soap to not to contaminate the water. Once you’ve finished washing up in the Sento, wipe your body dry and head to the locker room to redress, and you’re all done!

How to Take Onsen Bath: The Right Way

Step 1: Wash Your Body Before Entering

Before entering the onsen pool, washing your body squeaky clean is the foremost step. This is critical in preventing the water from being dirtied. Can you imagine how nasty the water would be if everyone soaked in the onsen without washing up first? I wouldn’t even dare step foot in one!

Cooling your body with cold water is highly recommended before entering the warm onsen bath.

Step 2: Douse Your Body with Warm Water

Practice the art of “Kake-yu” by dousing yourself with warm water to get your body used to the hot spring’s temperature before entering it. First, start by pouring water from your feet up to your waist, then move your hands up to your chest. Lastly, pour the water onto your head to prevent hot flushes and dizziness post-bath.

Step 3: Lower Yourself into the Water Slowly

When entering the onsen, gently lower yourself into the water until your body is half in, then stay there to get used to the water’s hot temperature to prevent straining your body later on. Once you’re comfortable, move your limbs and slowly ease the rest of your body into the water.

Step 4: Soak In But Not Too Long

Being the kiasu Singaporean I am, I would love to soak in the onsen pool for the longest possible time to make my money’s worth. However, the longer you soak does not mean you’ll absorb more nutrients into your body.

The recommended duration of soaking is not more than 15 to 20 minutes. It’s important to note that immersing yourself in hot water for too long will excessively raise your blood pressure or heart rate, causing dizziness and discomfort.

Therefore, the moment you feel uncomfortable, step out of the water and hydrate yourself immediately. Alternatively, soak for 15 minutes and leave for a cold bath before entering again.

Step 5: Do Not Shower After

It is advisable not to shower again after you’ve finished soaking in the onsen. This avoids washing off the medicinal components from the water and prolonging their benefits. However, if you do suffer from sensitive skin, you should rinse yourself off with fresh water to prevent any potential irritation.

Step 6: Wipe Yourself Down

Once you’re ready to leave, wipe yourself lightly with your bath towel before heading back to the dressing room. When drying off, try only to wipe off the beads of water to leave the nutrients of onsen water on your skin as much as possible. Afterwards, you could change into a Yukata bathing clothes (read on to learn how to wear one).

Step 7: Rest and Relax

Make sure you hydrate by drinking plenty of water. You probably won’t notice, but your body will have lost plenty of body fluids by now through sweating. Try not to line up any plans after soaking in the onsen, as you will deplete your energy levels. Resting your body for at least 30 minutes before stabilising itself again is important.

Onsen Etiquette: How to Behave?

When soaking in the pool, there are rules to follow before, after, and during the experience! Keep these etiquettes in mind; otherwise, you might have to leave the onsen without even getting to dip your toes in.

1. No Photography Allowed

onsen singapore - No photography

“Picture perfect memories”, I get that. But save your Instagram pictures later, as this is not where anyone wants to get photobombed.

An onsen is a place for everyone to relax and not be wary about who will snap a photo of them half-naked.

2. No Tattoos Allowed

onsen singapore - Lady back with tattoos

In Japan, tattoos are deemed uncool as they have gang ties. Therefore, people with tattoos are prohibited from entering communal onsens. Yes, even those of you with tiny tattoos, unfortunately!

That’s not the end of the world, though! People who have their bodies inked can still opt for a private soak at a typical onsen resort.

3. Be Prepared Not To Wear Anything

onsen singapore - Naked lady in onsen

If you’re self-conscious about going in naked and wish to bring a swimsuit along, I’m sorry, but you will not be allowed to enter the onsen. As one local Japanese person once told me, “You go in as you came into this world”. That means you’ll have to remove even your undergarments before entering!

Thankfully, Ikeda Spa provides disposable undergarments for beginners to ensure that everyone’s comfortable!

#FunFact 1: In Japan, there is a phrase – 裸の付き合い (Hadaka No Tsukiai) which translates to ‘naked friendship’. The Japanese will only reveal their body to the people whom they trust the most. Barriers are broken down once you are naked, and it is a good chance to relax and talk openly and honestly.

4. Tie Your Hair Up

onsen singapore - rinse water

If you have long locks, tie your hair up, as the onsen bath is only meant for soaking your body. For sanitary purposes, avoid having your hair touch the water.

5. Pour Hot Water Over Your Body First

Japanese people prefer onsen temperatures between 39°C to 42°C for the best comfort. If your body is cooler before getting into hot water, you’ll feel the heat even more. So, it’s a good idea to splash some warm water on yourself before getting into the pool.

And Japanese call this ‘Kakeyu’. Kakeyu means the onsen water you scoop up with a bucket and pour on yourself. This tells your skin and body that the onsen’s temperature is like this.

Kakeyu should be poured on your body from the regions farthest from the heart to the nearest. All in all, ten scoops of water should do the trick. The recommended sequence is:

Right foot → left foot → right knee → left knee → right hip → left hip → stomach → right shoulder → left shoulder → back

Ten scoops is a rough guide, not a strict rule. Around that many scoops should work. The goal is to acclimate your body to the heat, making it easier to get into the onsen. Warming up with some exercises can be helpful for your body.

#FunFact 2: This act is also symbolic, purifying our bodies by washing away the worries of everyday life. It’s like giving ourselves a fresh start before entering a natural onsen. This idea aligns with Buddhism and the local culture in Japan. It’s not only about manners and being clean, although that’s part of it too.

Onsen Towels: How to Use Them Properly

onsen singapore - Towel on lady's head while she is taking an onsen

When you visit an onsen, they usually provide you with two towels: a small one for your face and a large one for your body. It’s important to only take the small towel into the communal bath area, as the large one is meant for drying off after your bath. Here are some tips on how to use the towels properly, like a seasoned onsen-goer.

1. Cover Up with the “Modesty” Towel

To enjoy an onsen, nudity is a must. Don’t worry, everyone else is naked too, and they couldn’t care less about your birthday suit. Being naked in an onsen is liberating, not embarrassing. Trust me, and you’ll feel more self-conscious if you’re the odd one out in a bathing suit. And yes, while it’s ok to be fully naked, it’s important to be modest. Grab your small towel and casually cover your private parts when moving around. Remember, most Japanese men and women do the same, adding a touch of elegance to the experience.

2. Don’t Drop Your Towel in the Water

Typically, wearing a towel in an onsen is not allowed, and it is important to ensure that your towel does not touch the communal hot spring water.

The reason why wearing a towel in an onsen and dipping it in the hot spring water is considered bad manners is due to hygiene concerns. As you are sharing the same bathwater with others, it is important to maintain cleanliness and sanitation.

Currently, many hot springs offer guests clean towels. However, in the past, individuals would bring their towels from home, which may not have been recently washed or have used unknown laundry detergent. Even a newly washed or brand-new towel could contaminate the onsen water with fibres or chemicals.

The purpose of an onsen is to cleanse the body and provide relaxation for the mind, as well as to enjoy the health and beauty benefits of the hot spring. Owners of renowned hot springs make efforts to keep their water clean and as natural as possible, avoiding the use of chemicals, even if they are government-approved and non-toxic. Their goal is to maximize the healing powers and benefits of the hot spring water by preserving its natural state.

3. Stop Wringing Water Out From Your Wet Towel

Accidentally dropped your towel into the water and attempted to dry it? Don’t wring it into the onsen bath!

I’m sure I don’t have to explain how wringing your perspiration into the water is unhygienic and disrespectful to the others soaking in the water after you. Instead, take it out of the onsen and wring it away from the bath. Alternatively, you can always ask for a new towel if needed.

Based on my personal experience, I recommend placing the towel next to the tub instead of on your head while soaking. This way, you can relax without the concern of accidentally dropping the towel into the water.

#FunFact 3: Notice people placing small towels above their heads? This is because the heat from the onsen will go through your body and all the way up to your head. The main purpose of the towel is to retain the heat from leaving your body and, at the same time, cool down your head to prevent dizziness.

How to Wear a Yukata: Video Tutorial

You’ve probably seen this kimono-lookalike around. A “yukata” (浴衣) is a casual, thinner version of kimono that is usually made of cotton or synthetic fabric to be wrapped around your body and fastened with a sash (obi). “Yukata” literally means “bathing cloth”, and the garment was originally intended to be just that. Traditionally, it is worn after bathing in an onsen, functioning as a quick way to cover the body and absorb remaining moisture.

Originally, many communal onsens just had simple indigo-dyed yukatas available. These days, however, more onsens have a variety of designs and colours, so guests can now have the freedom to choose the yukata that best suits them!

Putting on a yukata for the first time might be tricky, so we have created a quick step-by-step video to help you.

Onsen Benefits: Why Should You Soak In One?

Two words — relaxation and health benefits.

1. Reduces Stress

Warm baths generally aid in unwinding your body and mind after a stressful day. It helps that hinoki wood (the material commonly used to make traditional Japanese onsen tubs) also contributes to easing the mind of your worries.

Once in contact with hot water, this Japanese cypress wood releases hinoki wood oil that relieves anxiety and promotes balance. Its essential oil is widely used in aromatherapy to reduce the stress accumulated from school, work, or even life.

Ultimately, the synergy of hot water and hinoki wood is the perfect solution for melting the tension away.

#FunFact 4: Besides reducing stress, did you know that hinoki wood oil also acts as a decongestant of the respiratory system that cures asthma and other nervous system ailments? Amazing.

2. Boosts Blood Circulation

Researchers from Japan found that people who suffered from chronic heart failure and soaked in hot springs experienced decreased blood pressure and an overall improvement in their symptoms.

As you sit in the water, your blood pressure drops, your blood circulation goes up, and your metabolism kicks in a bit. I’m not going to lie; you’ll probably feel a little funny at first. But eventually, your body will automatically adjust to the temperature of the water and allow you to relax after that.

3. Nourishes Skin

Onsens that use hinoki wood are perfect for sensitive skin as it is gentle on the skin. In Japan, this Japanese cypress wood’s essential oil is traditionally used to treat skin irritations and injuries due to its antiseptic benefits. 

Being highly therapeutic with essential oils in it, it gives restoration treatments. When bathing in the hinoki onsen, your skin will soak up all the goodness, making it feel soft and supple.

#FunFact 5: Soap, antiseptics, perfume, cosmetics, and even hair treatments use the minerals and essential oils of Hinoki Wood! Now imagine all of the benefits of going for an onsen!

4. Relieves Pain

As you have so cleverly deduced by now, onsens are generally hot, typically measuring from 37°C to 42°C. This heat, although sometimes intense, can help relieve pain. The heat, along with the water pressure, dulls our perception of pain by blocking the pain receptors in our bodies. Interesting, right?

Moreover, the mineral concentration and hot water can make you feel “floatier”, positively affecting your joints and muscles as they work together to help you feel good and (more importantly!) more relaxed.

A review in Rheumatology revealed that spa therapy and balneotherapy (the “treatment of disease by bathing”) might also help relieve lower back pain, especially at higher temperatures.

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Useful Japanese Phrases When Visiting an Onsen

Experiencing a hot spring (onsen) is a highlight of any trip to Japan! However, language barriers can be complex, as many facilities need more English support. Here are some basic Japanese phrases to help you navigate this traditional and rejuvenating cultural experience!

At Reception Counter

1. “Hitori ikura desu ka?”

[hitori ikuradeska]

“How much for one person?”

Use this to inquire about the cost to enter. Some places might charge differently for kids and students, so you can ask the staff members.

2. “Basu taoru wa rentaru dekimasu ka?”

[bastaoruwa rentaru dekimaska]

“Can I rent a bath towel?”

“Taoru wa rentaru dekimasu ka?”

Use this sentence when you need to borrow a bath towel at an onsen or public bath. Some places give you a towel when you pay to enter, but it’s good to confirm.

3. “Shanpu (sekken) wa arimasu ka?”

[shanpu:,sekkenwa arimaska]

“Is there shampoo (soap)?”

You can say this to check if they have shampoo and soap. While big onsen places in hotels and popular spots usually provide these, some public bathhouses might not.

4. “Tatu wa daijoubu desu ka?”

[tatwu daijo:budeska]

“Are tattoos allowed?”

If you have tattoos, ask if they let people with tattoos use the onsen. More places are becoming okay with tattoos, but some still don’t allow them. It’s also okay to use special stickers to cover your tattoos.

Entering the Bathing Zone

5. “Onna-yu wa doko desu ka?”

[onnayuwa dokodeska]

“Where’s the women’s bath?”

“Otoko-yu wa doko desu ka?”

[otokoyuwa dokodeska]

“Where’s the men’s bath?”

At many onsen and sento places, they put up red noren curtains for women and blue noren curtains for men. But if you’re unsure, you can use this sentence to inquire about which curtain is for women and which is for men.

6. “Koko wa aitemasu ka?”

[kokowa aiteimaska]

“Is this available?”

You can use this phrase to ask if there’s a changing room, locker, or shower available for you to use.

7. ”Tsukattemo daijobu desu ka?”

[tsukattemo daijo:budeska]

“Can I use this?”

You can use this sentence to inquire whether you can use a basket for your clothes, a locker, a shower, a dryer, or any other item.

After You’re Done Bathing

8. “Kyu-kei su-pe-su wa arimasu ka?”

[kyu:keisupe:suwa arimaska]

“Is there a lounge?”

Use this phrase if you’re looking for the lounge area after you get out of the bathing area.

9. “Shokuji wa dekimasu ka?”

[shokujiwa dekimaska]

“Can I eat here?”

In some places, you might not be permitted to bring in outside food or drinks, and eating or drinking might be completely prohibited on the premises. To check whether eating or drinking is allowed, you can use this phrase. Also, remember that certain onsen and public bathhouses have their restaurants on-site.

If You’re Feeling Unwell

10. “Gu-ai ga warui desu.”

[guaiga waruides]

“I don’t feel well.”

Say this if you start feeling unwell after entering the onsen. If you’re not feeling good, don’t push yourself to stay in the water. Reach out to a staff member or the people nearby for assistance.

11. “Memai ga shimasu.”

[memaiga shimas]

“I feel dizzy.”

If you feel unwell after entering the onsen, use these words. If you’re not feeling well, don’t force yourself to stay in the water. Instead, reach out to a staff member or the people around you for help.

12. “Hakike ga shimasu.”

[hakikega shimas]

“I feel nauseous.”

If you feel like you might vomit, use this sentence. The smell of sulfur at hot springs can affect some people negatively. Say this to ask for assistance from those nearby.

Onsen Food: Delicious Cuisine & Snacks

Japanese invented a unique cooking method to utilize the warm water from the onsen for their cuisine. The technique originated before the Edo period and is considered a healthy cooking method as the food absorbs minerals from the hot springs.

1. Steamed Onsen Eggs

Onsen Tamago (温泉卵) translates to ‘hot spring eggs’ and is essentially eggs prepared in hot spring water to create silky egg whites and a custard-like yolk. The egg is cooked by being steamed in a bamboo basket and is typically served with either salt or soy sauce. Because it’s cooked using onsen water, you can taste the delicious mineral flavour!

Onsen Egg

If you reside in Malaysia or Singapore and are familiar with half-boiled eggs, you’ll be happy to know that onsen eggs are similar but slightly firmer.

There’s no need to bring these eggs to an onsen to cook. All you need is one cooking pot and enthusiasm to make this delicious Onsen Tamago in the comfort of your own home!

How To Cook Onsen Eggs At Home
Onsen Egg in Bowl
What You’ll Need:
Cold Egg
Cooking Pot
A bowl of Icy Cold Water

Step 1:
Fill your pot with water. Boil till water starts to a rolling boil.

Step 2:
Remove the pot from the heat. Wait 1 minute and place cold eggs into the water without covering the pot with a lid. Do not try to move eggs.

Step 3:
After 12 minutes, remove the eggs and put them back into ice-cold water. Ensure to cool the egg for 5 to 10 minutes until completely cooled.

Step 4:
Gently crack the egg open, and the egg will roll right out. Do not crack open from a height. Otherwise, the egg white will separate from the egg yolk.

And voilà, you’re all done! Make sure to enjoy your onsen egg with some soya sauce!

2. Cold Milk

Onsen Milk on Table at Onsen Bath

There are various theories, but there is no exact reason. One of the most prominent explanations has to do with the war. After the war, when refrigerators were not widely used in ordinary households, public baths worked with milk producers because they used refrigerators to provide cold drinks.

Drinking water after a bath is essential because you’ll be dehydrated. And you can now get Fruit Gyuunyuu (“fruit milk”) or Coffee Gyuunyuu (“coffee milk”) at most onsens nowadays!

3. Onsen Buns

Locally known as Onsen-manju (温泉饅頭), this steamed bun is filled with sweet red bean paste and can be commonly found in towns and resorts of hot springs. The colour of Onsen-manju can be either white or brown, and it is not uncommon to come across unique variations that cater to different preferences.

It is supposedly named after that hot spring water is used for its dough, and the steam from the hot spring is also used for steaming the buns, making them even more fluffy than usual. The bun is available in both small and large sizes, and it is a satisfying way to end a hot spring meal. This delicious dessert is perfect to buy as a souvenir or to eat while enjoying the beautiful view from the onsen resort!

Onsen Beauty: Skincare Tips & Hacks

In Japan, people believe that onsens can make skin look better. They’ve found a special way to use onsens for beauty treatments, and we’ll tell you about it today!

1. Do Your Skincare Routine Right After Soaking

On the whole, Japanese onsen contains components that leave the skin looking fresh and feeling great. After you emerge from a good onsen soak, you’ll feel like your skin has been reset – ready to take on new challenges. Beauty products will be absorbed easily by your skin during this period, so we recommend going through your skincare regime in the dressing room of the onsen if you can! There’s no need to use anything special – just what you usually apply. The products will be absorbed more quickly than usual, and their effects will be more evident as well!

2. Steamed Onsen Towels

If there’s a hot spring tap dispensing fresh onsen water, get a bucket from there and wash your face with it! Some people try to soak without letting a single drop of onsen water touch their faces, but that’s a waste of good water! Of course, the water from the tap will be really hot, so wait for it to cool down to a nice, warm temperature you’re comfortable with before washing your face with it. Or you could dip your towel in the bucket, wring out the excess water, and place the towel on your face. It’s like getting a luxurious steamed onsen towel facial mask treatment right in the hot spring!

If you are taking a private onsen bath, you can do the steamed towel treatment right inside the onsen bath itself. Place a hot towel on your face and wait until it cools down. This Japanese skin care beauty regimen can be done while enjoying a hot spring soak. What’s not to love about it? It’s simply irresistible!

3. DIY Onsen Face Masks

You’ll need a portable plastic bottle for this. Collect water from the onsen water tap to take home or to your room at the resort, allowing you to enjoy your own indoor onsen facial treatment at your convenience!

To create an onsen face mask, soak a plain sheet mask in collected spring water. It’s basically going to act like sheet masks sold on the market that come presoaked with the nutritious serum! Although face mask application can be done at the bathhouse, it is possible to feel lightheaded if you spend too much time in the bath. Therefore, it is recommended to bring the water back to your room or resort to try this onsen beauty treatment.

Leaving a sheet mask on too long can cause it to dry out, defeating the purpose of the treatment. Keep the mask on for about five minutes. Don’t let the onsen water sit for too long in the room. Use it while it’s fresh for the best effect. If bringing it home, make sure all collected water is used within three days of collection.

Onsen Water Colours: The Science Explained

If you’re under the assumption that all onsens are clear in colour, get ready to have your mind blown.

The colour changes depending on the elements and comes in various colours, giving you different features and benefits when done soaking.

1. Milky White

Milky White Onsen

Milky white water is also known as Lou-sen water.

Sulfur is the element that turns water into an aesthetically pleasing colour. When the fine particles of sulfur cannot dissolve, they get exposed to the environment and oxidize with hot water. Although they are typically colourless and transparent, they turn clear water into a beautiful milky white hue when in contact with air.

Unsure if you are soaking in the Lou-sen water? You’ve got your answer if it smells like a rotten egg scent.

The benefits of this onsen are impressive despite its unique foul smell. Here are some of its benefits:

  • Clears one’s throat
  • Enlarges blood vessels
  • Effective for heart diseases, arteriosclerosis, or other skin diseases
  • Helps with chronic bronchitis
  • Drug addiction treatment
  • Detoxification effects

Are you amazed yet? Just look at how beneficial it is to your body!

It’s also interesting to note that many onsen places with great water have this Lou-sen water in Japan. And yes, you guessed it—that makes it a prevalent type of onsen in Japan.

Travelling to Japan and want to try soaking in the Lou-sen water? Here are the places you can visit:

2. Brown / Red

Brown or Red Onsen

This reddish-brown onsen water is also known as Gantetsu-sen water.

The element that turns the water into this colour is iron. Similarly, iron is colourless and transparent like sulfur, but it turns the water chalky and changes its colour into a reddish-brown tint when oxidised.

One notable feature I’d like to highlight is its rust-smelling water. Although I won’t advise you to taste the water, you can still do so (if you’re adventurous) and find that it tastes not very pleasant.

Soaking in the Gantetsu-sen hot spring allows your body to capture the iron and brings you these benefits:

  • Helps with anaemia
  • Good for menopausal or menstruation disorder
  • Improves blood circulation

Having been known for bringing positive effects mainly for women, some call the water Fujin-no-yu, otherwise known as the Water of Women.

If you’re in Japan and wish to try this onsen, you can try:

  • Tatsuno-yu Onsen, Hyogo Prefecture

3. Black

Black Onsen

If you’re one for gothic culture, this Kuroyu (“Beautiful Skin Spring”), otherwise known as the black onsen, is the perfect place for you.

The cold mineral spring of humic acid turns the water black because of the size of its particles. Bigger-sized particles turn the water black and opaque, while smaller-sized particles turn the water light-black and transparent.

With abundant minerals from the leaves and grass, this pretty hot spring brings these benefits:

  • Positive effects on skin
  • Warming to the core of the body

Seeking to improve your skin conditions in Japan? Then below are the places you should head to:

4. Green

Green Onsen

This green water is known as Moor Onsen due to the composition of organic vegetative substances.

The soothing and light green Moor Onsen contains fulvic acid, sodium hydrogen bicarbonate, and sulfur. However, the mechanism of the tone of the water is still unclear.

All in all, taking a dip in this pool can bring you these beauty benefits:

  • Rid toxins
  • Prevent cells from oxidizing (anti-ageing)
  • Tenderizing effect
  • Removal of dead skin cells

By removing your dead skill cells and providing you with anti-ageing skin properties, this “Hot Spring of Beauty” is sure to keep your skin protected and renewed!

To get these beauty benefits, the to-go place in Japan will be:

5. Blue

Blue Onsen

This blue water is a combination of milky blue and milky white water.

However, just like the green water, the mechanism of the blue water has not been clarified yet. Thus, it is only said that silicic acid and sulfur components are related to turning the water blue.

Known for these benefits, you can expect this from the water:

  • Strong moisturizing and soothing effect
  • Aiding neuralgia
  • Relieves muscle soreness and joint pains
  • Improves blood pressure
  • Eases fatigue

Looking for the perfect retreat to rejuvenate your body? Visit these places in Japan:

Onsen Scent: What Are The Different Aroma?

It’s no secret that onsen water has a distinct smell, the most notable being a sulfurous one as you approach a hot spring town. But did you know that onsen comes in many scents besides sulfur? 

1. Sulfur

Most people describe this smell as similar to the scent left lingering after shooting a gun or the end of fireworks. The scent is most prominent in onsen waters that contain hydrogen sulfide. Even a small amount of hydrogen sulfide is strong enough to produce an overpowering smell. Fun fact? The milkier the water, the stronger the smell.

2. Rusting Iron

Now, this may be the easiest one to spot. If your onsen water has a brown or orange tinge or leaves a reddish tint on your tower after soaking, this water is high in iron and will smell rusty. Though it’s not as overpowering a scent as sulfur, your nose will still pick up the slightly pungent smell of such an onsen. 

3. Tar

The mild smell of this onsen water may remind you of burning rubber, oil, or leather on a hot summer’s day. This is because the onsen water gets infused with sedimentary deposits before pooling into a large body of water to form a hot spring.

4. Minerals

If your onsen water smells appetising, chances are you’re in a hot spring full of minerals. The subtle scent is something akin to kombu broth and can be found typically in mountain onsen. 

5. Iodine

Iodine-concentrated water is strongly associated with the smell of mint or mouthwash. This unique water may also come in a deep red or orange tinge that can help you distinguish the difference between that and other onsen aromas.

6. Salt

Lastly, we have salt-infused onsen water. As you’ve probably already guessed, these waters smell like the sea and can often be found in onsen, located by the seaside, where a higher concentration of chloride can be found. 

At Ikeda Spa, we have our own Hinoki Onsen Bath that gives you five different bath salt choices with an array of fragrances to choose from and releases mineral oils with soothing scents from the natural Hinoki wood for aromatherapy.

BONUS: Download Onsen Bath Infographic

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Did You Know that Ikeda Spa is the FIRST Onsen in Singapore?

Onsen Singapore in Clarke Quay

Are you excited to visit one now? But have no trips planned to Japan? You can always come to Ikeda Spa for your regular dose of onsen goodness. And if you want a more private soaking session with your loved one, we provide private onsens and couple onsens.

Did I forget to mention that the onsen bath is free if you book any 90-minute treatment at Ikeda Spa? What are you waiting for? Click on the banner below to find out how!