At least six people died as an overcrowded ferry sank near the tourist resort of Pattaya in eastern Thailand.
The dead included three Thais, two Russians and a Chinese, police said, adding that 15 people were seriously injured, including a Russian boy.
The rest of the passengers were rescued.
The double-decker ferry sank after reportedly running into engine trouble at around 17:00 local time (11:00 GMT) on Sunday, police said.
"Witnesses said there were neither enough tubes nor life vests on the ferry. Some of those who cannot swim had to cling onto coolers or ice containers until rescuers came," police Col Suwan Cheawnavinthavat was quoted by the Associated Press as saying.
Stunned tourists were shown on local television being led to safety on shore where they were met by dozens of ambulances in Pattaya, which is about 100km (60 miles) south-east of Bangkok.
Police want to talk to the ferry captain to try to ascertain the cause of the accident, Col Suwan said.