Ko Sak (เกาะสาก) is an island off the coast of Pattaya.
Six hundred metres north of Ko Laan is Ko Sak, a small island shaped like an upturned horseshoe. There are two connecting beaches to the north and south. Along the south shore are ranges of corals. Accommodation is available.
The north beach is popular for swimming and snorkelling, and the south beach is a good place to see coral.