Sixteen species are recorded in this survey of common intertidal and shallow subtidal sea anemones (cnidarian order Actiniaria) in Singapore. Six have previously been reported from Singapore in the scientific literature; 10 are new records for Singapore. The 16 species belong to families Actiniidae, Actinodendridae, Aiptasiidae, Boloceroididae, Diadumenidae, Stichodactylidae, and Thalassianthidae. Most are widespread in the Indo-Pacific tropics; Singapore represents the westernmost occurrence of three of the species that have previously been known only from along the western rim of the Pacific Ocean. Diadumene lineata is a cosmopolitan, invasive species.