Sanya's attractions divide between the beaches (Yalong, Dadonghai, Sanya Bay, Haitang Bay), the cultural-scenic complexes along the coast west of the city (Nanshan Temple, Tianya Haijiao), and a handful of inland and offshore destinations (Wuzhizhou Island, Luhuitou Park, the Tropical Botanical Garden).
If your time is short: half a day at Yalong Bay or Dadonghai, half a day on the western coastal loop (Nanshan and Tianya Haijiao together), and a day trip to Wuzhizhou Island covers the essentials. Luhuitou Park is worth the climb at sunset for the panorama. The Sanya International Duty Free Mall in Haitang Bay is a tourist attraction in its own right whether you intend to buy anything or not.