Ko Mai Si

Ko Mai Si or Ko Mai Si Don (Thai: เกาะไม้ซี้) is a small island near Ko Kut (Thai: เกาะกูด) in Trat province, Thailand.

It is only a small island in a group of Kut islands. Ko Mai Si is located about 1 km from the island Koh Kut and has an area of about 1.6 km2.