The foreign tourists were returning to Phuket from the Phi Phi Islands on Wednesday evening when the driver of the speedboat suddenly rammed into a concrete pillar, around 100 meters off Chalong Bay, the Thaiger news portal reported.
The injured tourists include four Thais, 21 Russians, and nine Kazakstanis. Three others came from Hong Kong, mainland China and Ukraine.
They are being treated at different hospitals in Phuket with each entitled to 15,000 baht ($440) insurance.
Phuket Governor Narong Woonciew said the relevant foreign embassies had been informed to provide assistance to the victims.
Police have tested the driver’s blood alcohol level and are awaiting results.
An investigation is ongoing.