Sheraton Okinawa Sunmarina Resort — Okinawa's only resort with a 60-metre water slide
Picture the look on your children's faces when they spot a water slide taller than a house, stretching 60 metres down to the pool — and then consider that only one resort in the whole of Okinawa has this. Sheraton Okinawa Sunmarina Resort is that place. A score of 8.6 from 1,580 reviews — the largest review sample on Onna Coast — is proof that what's advertised here actually delivers in real guest rooms.
Sheraton Okinawa Sunmarina Resort is set in Onna Village on the Onna Coast, about 55 minutes from Naha Airport via the Expressway. That's not close — but this resort is designed so that you genuinely don't want to leave for three to five days. There's a 200-metre private beach, an outdoor pool complex with three water slides, and rooms with sunset views over Onna Coast beautiful enough to sit on the balcony watching for hours. A score of 8.6 from 1,580 reviews is evidence that the gap between promise and reality here is reassuringly narrow.
"The biggest water slide in Okinawa — our kids wouldn't get out, they played all day and we nearly forgot to eat. The kids' breakfast section is excellent too, they helped themselves."
What separates Sheraton Sunmarina from every other resort on Onna Coast is the outdoor pool complex with three water slides at different heights — a gentle kids' slide, a mid-size slide, and the headline act: a 60-metre slide that children aged 6 and over can use with an adult watching. Many families say their kids rode the slide from morning to evening without stopping, which meant parents actually got to sit on a poolside chair and breathe — rather than chasing children around the property all day.
The private beach is equally strong. The 200 metres of sand comes with a lifeguard on duty from 9:00 to 17:00, so younger children can splash safely in the shallows. The water along Onna Coast is clear enough to see coral through the surface with the naked eye. For families travelling with small children, having a private beach rather than a public one — especially one with a lifeguard — is a meaningful difference.
The Sunset Family Twin room measures 36 sq m and features two double beds alongside sunset views of Onna Coast — views that many guests cite as the trip highlight. Four people fit comfortably. For five, or for families who want space for the kids to run indoors, the Marriott Premier Family at 48 sq m is a two-bedroom suite. Bathrooms here are larger than the resort average, which matters when a family of four is queuing for the shower.
The breakfast buffet includes a dedicated kids' section with a pancake bar, seasonal fruit, and multiple milk options — designed so children can fill their own plates independently from the start. Adult options follow the full 4-star Japanese hotel buffet format, with both Japanese and Western choices. Marriott Bonvoy members can redeem points for free nights and access elite status benefits in the usual way.
Honesty matters here, so a few things to know before booking. The 60-metre slide is open in summer only — April to October. Coming between November and March means the slide is closed, and while there is an indoor pool and an underground onsen open year-round, children expecting the big slide may be disappointed. The location on Onna Coast also means Naha is 55 minutes away and Churaumi Aquarium is another 50 minutes — a hire car is essential. The last renovation was in 2017, so rooms in some wings feel older than newer-built competitors, though maintenance standards remain solid.
Realistically, for families coming to Okinawa who want a water slide + private beach + Marriott Bonvoy benefits in one place, Sheraton Sunmarina has almost no competition on the island. The 8.6 from 1,580 reviews tells you that expectations and reality align well. Just make sure you come between April and October to get everything this resort is best known for.
Summary from Booking & Agoda
- ✓ 60m water slide — Okinawa's only resort with this feature, kids love it
- ✓ 200m private beach with lifeguard — safe for young children to swim
- ✓ Breakfast buffet with a dedicated kids' section — pancake bar, seasonal fruit
- ✓ Marriott Bonvoy — redeem points and access elite status benefits
- ! Slide pool closed November–March — children may be disappointed out of season
- ! Onna Coast is 55 min from Naha and 50 min from Churaumi — car hire essential
- ! Last renovated 2017 — some room wings feel older than newer-built resorts
- ✓ 1,580 reviews — the largest sample on Onna Coast, high confidence
- ✓ Three water slides for all ages — kids can play from morning to evening
- ✓ Private beach with clean sand and clear water
- ✓ Sunset Family Twin sunset views over Onna Coast are genuinely beautiful
- ! Price from ¥26,000 rises sharply during Golden Week and Obon
- ! Families of five need to upgrade to the Family Suite at ¥45,000+
- ! Indoor pool only in winter — no slides outside peak season
- 💡If you're coming November–March — the 60m slide pool is closed and children may be disappointed → consider shifting to April–October, or accept that you'll have the indoor pool and onsen instead.
- 💡If you're not hiring a car — Onna Coast has no public transport and Naha is 55 minutes away → hire a car at Naha Airport before making this your base for day trips.
- 💡If you're a family of five or more — Sunset Family Twin at 36 sq m will feel tight → upgrade to the Marriott Premier Family (48 sq m, 2-bedroom) or Family Suite at ¥45,000+.