At least 33 people were injured and two others are thought to be missing after two speedboats collided in the Gulf of Thailand.
The collision occurred as the boats were ferrying people to and from a full moon party on a beach on Koh Phangan, a monthly event on the island that is particularly popular with thousands of Western backpackers.
Two local hospitals told AFP they had treated 33 tourists between them, with nine still in their care.
The Nation newspaper website said two people were missing and 39 were injured, two of them in a serious condition with head injuries, after the crash threw them into the sea.
The Department of Foreign Affairs said it has not received word that any Irish citizens were caught up in the accident.
