My family and I had a lovely 4-day break at the Ritz Carlton - it represents an excellent choice for holidaying in Sanya. The service is mostly excellent (the necklaces on arrival are a nice touch), the food is superb (the breakfast buffet is wonderful, with a large choice of tropical Hainan fruits, including coconuts), there are 3 huge outdoor swimming pools, a kids swimming pool and activity centre, and the property is based in a more secluded part of Yalong Bay, which means beach time should be relatively peaceful. Its easy to call taxis from the hotel and the service staff are glad to help with destination advice, lending umbrellas etc.
If we had to make a small criticism, it would be that some areas are a bit too monetized i.e. designed around getting guests to part with money. Other hotels we've stayed have given soft teddy bear toys to kids as standard - here you must pay. Use sand toys for the beach.. you must pay. Use a giant inflatable toy in the swimming pool.. can we rent one for half an hour? No, you must pay.
Finally when making a booking, ensure your room is in the newer part - we experienced both older and newer wings... the latter is a step up in terms of comfort. Our room was spacious, with its own private balcony, plentiful supply of fruit, coffee pods, and drinking water, and was equipped with all the mod-cons you'd expect. We really enjoyed our time in the Ritz-Carlton - its design, service, food, features and proximity to the beach are all first-rate.