Electricity & sockets

The voltage on Koh Chang island (and in Thailand in general) is same as in the EU i.e. 220-230 V AC.

Socket Thailand

The sockets have either flat holes (and in that case you need an adapter that can be bought in all electronics shops) or mostly the adapter (reduction) is not needed at all, because the sockets are universal and can accommodate plugs both with flat or round (European) poles.