5 Best Water Parks in Japan and Tips for Visiting
Last Updated on August 17, 2025 by Kay
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Are you a water park enthusiast who is thinking of visiting one in Japan? Or maybe you’re just looking for a place to cool down and get some respite from the heat.
Japan has some awesome waterparks, so in this article, I thought I’d share the top five that are bound to leave a lasting impression on every visitor. I’ll also share some tips that everyone should know before they go to a water park in Japan.
Table of Contents
The Top 5 Best Water Parks in Japan
Here are the top waterparks that people living in Japan are obsessed with.
1. Nagashima Spa Land’s Jumbo Seawater Pool
This is a massive waterpark, one of the world’s largest, that’s located within Nagashima Spa Land in Mie Prefecture. It’s common for people around Japan to travel here just to go to this water park — in fact, my neighbors in Osaka make it a yearly event!
This water park has it all — pools that make you feel like you’re rafting (but in a swim ring), water guns, water wheels, and several water slides (including one that is 25 metres high). Children can enjoy the massive water playgrounds that cover a whopping 1,600㎡!
They have heated pools as well as an indoor pool area for small kids.
If you get tired of the pools, you can enjoy their amusement park that boasts several roller coasters, including the world’s longest roller coaster!
Nagashima Spa Land’s water park is open from July 12th to August 31st.
Fun Fact: The water at Nagashima Spa Land is actual seawater brought in from Ise Bay.
2. Tokyo Summerland
There is so much to do at Tokyo Summerland that it’s hard to keep count! This water park in Tokyo is mainly known for having the longest lazy river in the country, but they also boast a huge indoor pool with interactive water play areas for kids.
Of course, they have an impressive number of outdoor water park features such as slides, playgrounds, rock climbing, a water-based treehouse, and waterfalls. If you want to go down a slide with your family or friends, there’s one that has an inflatable raft where you can cruise down with up to 4-5 people!
Tokyo Summerland has plenty of rides as well in the amusement park section.
Tokyo Summerland is open from July 5th to September 29th.
The indoor pools at Tokyo Summerland operate from March 22nd to October 19th.
3. Hirakata Park’s THE BOON
Located in Osaka, Hirakata Park is another amusement park that has a water park during the summer. This is hands down the best water park for all ages in Osaka, especially for adults.
There are pools for every mood: one for lazy floating in a swim ring, a deep pool if you actually want to swim, a kids’ pool with its own mini water playground, and some massive water slides (a few cost 400 yen extra). There’s even a pool where you can look out over the city below.
THE BOOM is open daily from July 19 to August (except August 28). In September, it’s open on the 7th, 13th, 14th, and 15th.
Fun Fact: Hirakata Park, where THE BOON is located, has been around since 1910, making it one of Osaka’s oldest amusement parks!
4. Spa Resort Hawaiians
A little off the beaten path, Spa Resort Hawaiians in Fukui Prefecture is an indoor water park that you can enjoy year-round. Interestingly, the water is from Iwaki Yumoto Hot Springs (thank you, volcano-rich Japan), so the pools are warm and you can feel like you’re enjoying an onsen without having to get naked.
Spa Resort Hawaiians has three waterslides, including one where you can slide down with a friend or family member. They also have pools that cater to different ages, such as a pool for babies.
There’s even a full Polynesian-style stage show, complete with hula dancers and fire knife performances, that’s been running for decades.
If you like, you can stay overnight at their on-site hotel for the full mini-vacation vibe.
5. Yomiuri Land’s WAI
Located less than an hour from Tokyo’s Shinjuku Station, Yomiuri Land is known for its rides as well as beautiful night illuminations in winter. In summer, though, people flock to Yomiuri Land for their water park called WAI, which stands for Water Amusement Island.
There are five pools, including a lazy river, a kids’ pool, and a wave pool that actually feels like the beach (minus the sand in your shoes). This water park also has water playgrounds, plenty of slides, as well as a night pool and live music shows that you can enjoy while you’re swimming!
During the summer, WAI opens from June 28th to September 15th.
Comparison of the Best Water Parks in Japan
Wondering which water park in Japan is right for you? Here’s a quick comparison to help you decide.
Water Park | Vibe | Highlights | Price (Adults) | Best Time to Go |
| THE BOON (Hirakata Park, Osaka) | Adult-friendly but still kid-safe | Lazy river, deep pool, kids’ water playground, city-view pool, huge slides (some ¥400 extra) | ¥2,900 | Weekdays in late July or early Sept |
| Tokyo Summerland (Tokyo) | Tropical resort meets theme park | Indoor wave pool, jungle slides, warm pools, outdoor lazy river, thrill slides | ~¥3,900 (summer) | Weekdays before school holidays |
| Spa Resort Hawaiians (Fukushima) | Hawaiian vacation without leaving Japan | Giant indoor pools, water slides, hula & fire dance shows, hot spring baths | ~¥3,500 | Year-round (great for bad weather days) |
| Nagashima Spa Land (Mie) | Massive theme park + huge water park | Japan’s largest water park, multiple wave pools, extreme slides, hot spring resort next door | ~¥4,000 (water park only) | Mid-week in late Aug for smaller crowds |
| Yomiuri Land’s WAI (Tokyo) | Water park + amusement park in one | 5 pools (lazy river, kids’ pool, wave pool), slides from chill to extreme, shaded rest areas | ~¥3,300 (water park only) | Weekdays in July or early Sept |
Tips for Visiting Water Parks in Japan
Before you visit a water park in Japan, make sure to read these tips so you’re prepared!
Be careful about revealing swimwear
Japan is a fairly conservative country, and people tend to cover up, and this includes swimwear. You’ll see some young women wearing bikinis, but very rarely will you see very revealing swimwear. For instance, thongs are an absolute no-no. Make sure your bathing suit top isn’t too skimpy either.
Of course, no one will tell you to leave (as far as I know), but you might make some people uncomfortable. (For instance, my daughter started laughing when she saw an international tourist’s butt sticking out of their bottoms at a pool in Japan.)
If you’re unsure, bring some swim shorts and a rash guard just in case you feel the need to cover up.
Tattoos are usually not allowed
If you have a visible tattoo, there’s a good chance you won’t be allowed in the water park or pool, or you’ll be asked to leave. Most water parks in Japan have this rule, and they are quite strict about it.
To prevent this from happening, you can wear a rash guard or cover up your tattoo with waterproof bandages.
Summer is busy
Something that’s a little unfortunate is that water parks in Japan are mainly open from July to August, and this is when students are on summer vacation. So expect these water parks to be packed during this time.
Japan Water Park Packing List
Wondering what to bring? Here’s what I recommend.
- Swimming suit
- Waterproof phone case
- Sunscreen
- Cash for lockers
- A towel
- Inflatable swim ring
- Sunglasses
- Something to drink (some water parks will allow you to bring your own food, too.)
Wrap-up: The Best Water Parks in Japan
From Osaka’s city-view floats at THE BOON, to tropical indoor getaways like Spa Resort Hawaiians, to the thrill-packed Nagashima Spa Land, there’s a perfect spot for every kind of summer day.
My advice? Pick based on your mood and maybe your tolerance for crowds. Weekday visits in particular are your best friend.
So grab your swimsuit, a waterproof phone case, and don’t forget the sunscreen (yes, even if you’re mostly indoors… trust me on this one). Summer in Japan is hot, but these parks help make the heat somewhat bearable.