Yacheng Confucius Temple is one of Sanya's more substantial historic sites, in the old Yazhou area west of the modern resort city. The temple was first established in the 11th century, though the present buildings mainly reflect later rebuilding.
It is worth combining with Yazhou Ancient Town, Dongtian Park, or Nanshan Temple on a day trip along Sanya's western coast. The appeal is historical rather than beach-focused, which makes it a useful change of pace.