Where on Hainan island is there parasailing, snorkeling, and surfing ?

Yalong Bay is highly recommended. There are many tourists and local people that play these activities. You can join them.
About the accommodation, you can stay at Grand Metropark Resort SY. This hotel has awesome living environment and warm service. The price is CNY 600 to 1,500 per night. It's located at Yalong Bay National Resort District. You can find it easily.