Among the dead are two Russian men, police said.
The van slid off a bend and slammed into a house in Muang District* at 7:30am.
The van was carrying 10 people from Phuket to Satun on a visa run operated by Phuket-based KBV Visa Run, said Capt Chatree Pienkhayai of the Phang Nga City Police.
In the van were Thai nationals, Russians and at least one Indonesian, he said.
Two Russians and one “Asian national” woman were reported dead at the scene when emergency first-responders arrived.
Three passengers were still trapped inside the van, forcing the rescue workers to use “jaws of life” hydraulic cutters to free them from the wreck.
The three dead and seven passengers, some of them with serious injuries, were all taken to Phang Nga Hospital in Phang Nga Town.
The van driver, Prawit Raweewat, 33, told police that it was raining when he lost control of his vehicle on the bend.
Calls to KBV Visa Run in Phuket this morning were not answered.
* Not the neighbouring district of Thap Put as originially reported.