Plenty of better Asian windsurfing destinations than Hainan Island !
Its sold as the Hawaii of the east but its just marketing crap. Yalong bay in Sanya is ok but don't know of any sailboard centres there.
Expect to see 1 or 2 hotel kits available for hire that washed up from the set of Miami Vice in 1984.
Also inflation in China has sent prices sky rocketing so don't your expect $ to go as far.
If you want to come to asia try Mui Ne in Vietnam, Boracay Island Philipines or Makung Island in Taiwan way better !!!!
www.penghuwindsurf.idv.tw/www.windsurf-vietnam.com/#p/a/u/0/HVkPPz6fprg