Hainan has some of the best surfing beaches in China, and there are two easily accessible surf resorts on the east coast with foreign co-owners. Riyue Bay, 19km outside Wanning about halfway down the east coast, is home to the Riyue Bay Surfing Club who rent boards for ¥100/day; or you can get 2hr lessons in English for ¥400 (surfinghainan.com). Closer to Sanya, and with warmer water, Houhai Bay is where you’ll find the Karma Surf Hostel and School who have similar rates and surf from a number of different beaches depending on the season.
Northeastern and eastern swells bring waves of around 1–2m most of the year, though during typhoon season (June–Sept), waves will be more like 3–5m and sometimes up to 6m. Riyue Bay is a northeast open bay and probably better during the winter months, when it gets up to 5m waves, and is hence the setting for the ISA Hainan International Surfing Festival each January, and the smaller ASB Hainan Classic competition in November (hainaninternationalsurfingfestival.com). If you know your surfing, Houhai would be the Huntington Beach, and Riyue more like the Hawaiian North Shore.