Thai police said 97 people were on board the vessel when it got into difficulties sailing the Andaman sea on Thursday (July 5).
Some 49 people are still unaccounted for according to the island’s governor, Sky News reports.
A rescue mission is under way, with a relief centre set up at nearby Chalong Bay.
Earlier the same day, another boat, carrying 39 European and Chinese tourists, also capsized. All those on board have since been accounted for.
There are warnings of continued severe weather into next week in the popular tourist region.
