Seven were taken to hospitals in Phuket, reportedly with head or arm injuries, but none said to be in a serious condition.
The boat, carrying 37 tourists, three boat crew and a guide, left Phuket with other two boats from the same tour company this morning.
After some time at Phi Phi, with the weather deteriorating, the captains of the three boats decided to cut short the tour and take all the tourists back to Phuket.
The 13-metre Luk Pradu 26 was following the other two boats when it was hit by a large wave that damaged the bow of the boat. Water began to pour in.
“The sea was very rough today. After the water filled the boat, it began to sink quickly,” British tourist Samantha Chappell, 22, told The Phuket News. “I was very scared.
“Petrol leaked from the boat and burned my skin.
“We were floating in our life jackets for about an hour before we were rescued.”
The tourists on board the boat were a mix of nationalities – Malaysians, Indonesians, Australians, New Zealanders and Britons.
Pongsak Pachantabut, the manager of Phuket New Generation Travel, which organized the one-day tour from Phuket to Phi Phi, said the company would pay for the cost of medical treatment for all those hurt in the sinking.
Phuket Marine Police confirmed that an alert had been issued, warning people to be beware of heavy seas, but the warning did not prohibit boats from sailing.
The video below shows the tourists being pulled from the water, and gives a good idea of weather conditions at the time.