Tomamu Mina-Mina Beach: Japan's Biggest Indoor Wave Pool With Kids
Tomamu Mina-Mina Beach is Japan's largest indoor wave pool (30m×80m, 30°C+) — free for hotel guests year-round. Which hotel for a pool-focused family ski trip.
If your family wants to ski in the morning and swim in the afternoon — indoors, in warm water, while it's −15 °C outside — Tomamu Mina-Mina Beach makes that day possible. Japan's largest indoor wave pool (30 m × 80 m, kept above 30 °C) is free for all guests at Hoshino Resorts Tomamu, and it runs year-round. For a family trip centred on the pool, Tomamu The Tower is the most practical base, with rooms from ¥25,000 per room per night in low season (rates vary sharply; New Year rates are significantly higher). If budget allows, RISONARE Tomamu gives you 100 m² suites and a quieter pace — though both hotels share the same Mina-Mina Beach.
What Mina-Mina Beach is — Japan's largest indoor wave pool at Tomamu
Mina-Mina Beach is a purpose-built indoor beach hall at Hoshino Resorts Tomamu in Shimukappu, Hokkaido. The pool measures 30 m × 80 m, making it the largest indoor wave pool in Japan, and the hall is maintained at over 30 °C year-round — a deliberate contrast with the sub-zero temperatures outside in winter.
The pool generates waves every 30 minutes for a 10-minute burst, cycling between parallel waves and slightly larger rough-sea waves. A separate children's pool with a depth of 30 cm sits adjacent to the main pool, making it manageable for toddlers. After 8 pm the hall dims and the pool is lit differently, shifting the vibe from busy family swim time to a more ambient evening soak.
Admission is free for guests of both Tomamu The Tower and RISONARE Tomamu. Non-guests cannot enter. The pool runs all year — during the winter ski season (Dec 1–Apr 4, 2026 for the 2025-26 season) it is the resort's single most popular non-ski facility.
| Name | Area | Price range | Best for |
|---|---|---|---|
| Tomamu The Tower | Tomamu resort centre | from ¥25,000 /room/night | Families, budget-conscious, walkable dining access |
| RISONARE Tomamu | Tomamu hilltop forest | ≈2× Tower / verify current rates | Couples, luxury families, space and quiet |
Rates vary sharply by season; New Year and peak winter rates are significantly higher. Verify current rates before booking.
Waves, hours and access for hotel guests
Mina-Mina Beach is open daily for hotel guests and included in your stay — no separate ticket required, no booking needed. Operating hours during the 2025-26 winter season were 11:00 am to 8:00 pm (last entry 7:00 pm). Of the two resort hotels, both Tomamu The Tower and RISONARE Tomamu share full access to the pool (checked July 2026).
What to bring:
- Swimwear — available at resort shops if you forget
- Towels are available to rent or buy at the pool facility
- Water shoes are useful for the beach-style floor near the wave entry
- Lockers are provided inside the changing rooms
The pool complex also has rest areas with loungers inside the heated hall, so non-swimming parents can sit comfortably while kids play. From Tomamu The Tower, the walk to the pool building takes about 5 minutes through the resort's covered indoor passages — useful when it's snowing heavily.
Pairing the pool with a ski day — and staying warm when it's very cold outside
Tomamu is genuinely cold. During New Year week temperatures regularly drop below −15 °C at night, and even midday on the slopes can be −10 °C or colder. That is part of what makes Mina-Mina Beach so appealing as a complement to skiing — you can spend the morning on the mountain and the afternoon in the warm pool without ever being truly cold for long.
A practical ski-and-swim day looks like this: ski lifts open around 8:30 am and run until 4:00 pm; the pool opens at 11:00 am. Most families we spoke with on our New Year stay at The Tower would ski in the morning, eat lunch at one of the resort restaurants, then head to the pool from around 1:00 pm until 5:00 pm. Dinner reservations from 6:00 pm onward. The combination works well because neither activity requires transit — everything is within the resort footprint.
A note on snow: Tomamu sits further inland than Niseko or Rusutsu and gets colder, drier air. Snowfall totals can be lighter than the west-coast resorts in some years — my personal take from staying over New Year is that it felt slightly less powder-heavy than Rusutsu. The mountain has good skiing but the primary draw at Tomamu is the total resort experience, not powder-chasing. See Rusutsu vs Tomamu for a side-by-side breakdown.
The resort's indoor-outdoor design helps manage the cold day-to-day. The Tower's lobby, dining wing, and pool are all linked by covered internal walkways, meaning you rarely need to dress for outside temperatures just to get to dinner or the pool.
Other indoor and winter activities at Tomamu
Mina-Mina Beach is the headline, but it is not the only reason to stay at Tomamu in winter. The resort's confirmed winter programme for 2025-26 included several additional attractions:
Ice Village — Tomamu's best-known winter event. For 2025-26, Ice Village ran from December 10, 2025 to March 14, 2026, 17:00–22:00 (last entry 21:30). The village covers 3.2 hectares and features 11 ice and snow domes. Admission is ¥600 per person aged 7 and over; free for guests of The Tower and RISONARE Tomamu. Highlights included an Ice Restaurant serving hot cheese fondue and "Ice Ramen," an Ice Sweets Shop where kids can make chocolate treats in ice containers, and an Ice Museum commemorating the 20th anniversary of the resort's Ice Church. These attractions are confirmed for 2025-26; check the Hoshino Resorts TOMAMU official calendar for the 2026-27 season dates before booking.
Ski school for children — Tomamu offers ski lessons for kids. Specific age groups, lesson times, and English-language availability should be confirmed directly with the resort before arrival.
Sea of Clouds observation deck — This is primarily a summer activity (predawn lift ride for the famous cloud-sea views), but winter versions may operate on clear mornings. Verify current season availability on the official site.
New Year festivities at Japanese ski resorts typically include traditional mochi-pounding events and countdown gatherings, and Tomamu's atmosphere over shogatsu is lively and family-friendly from personal experience. Specific event names and schedules for any given New Year should be confirmed on the resort's official seasonal calendar.
Which hotel and room for a pool-focused family trip
Both hotels at Hoshino Resorts Tomamu grant identical access to Mina-Mina Beach, so the choice comes down to room size, budget, and how much you value proximity to dining.
Tomamu The Tower is the practical choice for most families. Family rooms sleep four comfortably in around 58 m², and the building is a short walk from the main dining wing and the resort's central facilities. It is the older of the two buildings — the décor shows its age in places — but the value-to-access ratio is strong. Child stay policies vary by room type; check at booking. Our New Year stay here confirmed the rooms are functional and clean, the location genuinely convenient, and the overall resort experience more than makes up for the dated interiors.
RISONARE Tomamu is the upgrade. All rooms are suites at 100 m² or more, each with a whirlpool bath and sauna. The hotel sits in a conifer forest on the resort's hilltop — quieter and more private than The Tower, but a shuttle ride away from many of the main restaurants. If your family wants space to spread out and a more resort-spa feel alongside the wave pool, RISONARE is worth the premium.
For a first-time family visit centred on the wave pool and winter activities, I'd recommend The Tower for its walkable access to dining and the pool. If your budget allows and you value room space above convenience, book RISONARE and factor in the shuttle times for meals. See the full Tower vs Risonare breakdown for a detailed room-by-room comparison.
| Name | Area | Price range | Best for |
|---|---|---|---|
| Tomamu The Tower | Tomamu resort centre | from ¥25,000 /room/night | Families wanting walkable pool and dining access |
| RISONARE Tomamu | Tomamu hilltop forest | ≈2× Tower / verify current rates | Families wanting luxury suites, jet bath, quieter base |
Rates vary sharply by season; New Year and peak winter rates are significantly higher. Verify current rates before booking.
For everything about getting to the resort, read our Tomamu where-to-stay guide. The short version: take the train to JR Tomamu Station — the resort's free shuttle meets arriving trains and reaches The Tower in about 5 minutes, RISONARE in about 10 minutes.
Two things sit around the pool day: taking children into an onsen, and how small the room is when the whole family is drying off in it.
FAQ: Tomamu Mina-Mina Beach
Is Mina-Mina Beach open in winter?
Yes. Mina-Mina Beach is an indoor, year-round facility kept above 30 °C regardless of outdoor temperatures. It operates throughout the winter ski season at Tomamu (typically December through early April). Hours during the 2025-26 winter season were 11:00 am to 8:00 pm, last entry at 7:00 pm. Check the Hoshino Resorts TOMAMU official site for the current season's schedule.
Is Mina-Mina Beach free for hotel guests?
Yes. Admission to Mina-Mina Beach is included in the cost of your stay at either Tomamu The Tower or RISONARE Tomamu — no separate ticket is required. The pool is not open to day visitors or non-guests.
How big is Mina-Mina Beach compared to other indoor pools?
At 30 m × 80 m, Mina-Mina Beach is Japan's largest indoor wave pool. The facility includes a main wave pool for adults and older children, and a separate shallow pool (30 cm depth) for toddlers. Waves run every 30 minutes in 10-minute cycles, alternating between parallel waves and larger rough-sea waves.
What other winter activities does Tomamu have besides the wave pool?
The biggest supplementary winter attraction is Ice Village — a 3.2-hectare compound of 11 ice and snow domes, confirmed for 2025-26 from December 10 to March 14, with entry free for hotel guests. Skiing and snowboarding are available on Tomamu's own mountain. Ski lessons for children are offered on-site. New Year stays include traditional seasonal festivities — confirm specific event programmes on the official resort calendar for your travel dates.
Information audit: Last fact-checked July 2026 · Prices checked July 2026 (all rates are “from” floors that vary by season) · Rates shown are winter ski-season “from” floors; the green (summer) season is cheaper. New Year (roughly Dec 28–Jan 4) is the annual peak: at Rusutsu the Westin is priced per person (room-only, Japanese style) over the holiday — firsthand, a New Year room for three came to about ¥360,000 for one night (roughly ¥120,000 per person, tax and service included), well above the everyday per-room ski-season rate — and Tomamu prices climb sharply too. Verify the pricing basis and your exact dates on the official sites. Lift-ticket, shuttle and event details are based on 2025–26 announcements and will be updated for 2026–27. · How this guide was researched: hotel facilities, prices and access details are verified against official and primary sources; we have not personally stayed at every property listed. The author has skied Tomamu and stayed at Tomamu The Tower over New Year · Personally stayed: Tomamu The Tower — a New Year stay — all stays paid by us; no complimentary stays · How this site verifies information: About NipponStays.
