Klong Son, is located at the north-east end of Ko Chang. It is approximately 1.5 kilometres wide, at the southern part scarcely 2 kilometres long and at the northern section easily 3 kilometres. Two small islands are located at each end of Klong Son Bay - Ko Chang Noi in the northwest and Ko Mapring in the southwest.

There are 2 beaches in Klong Son Bay, the long Chang Noi Beach that extends over the whole bay and the small Halfmoon Beach that faces the mainland. In the north the the two beaches are close together.