Thai authorities said on Friday that the death toll had climbed to 10 and was expected to continue rising. Authorities had already confirmed the death of another Chinese man.
The Royal Thai Navy said "quite a few bodies" had been found inside the sunken vessel, while others were found floating in the water. More than 20 people remained missing.
They said they don't know the nationalities of the other missing people, but those who had been rescued were mostly Chinese on group tours.
In the third accident, a dive boat named Phoenix with 105 people on board (93 tourists and 12 crewmen and guides) sank near Koh Heh.
Phuket's governor has declared the area a disaster zone.
Local police commander Teerapol Tipcharoen said earlier that the recovery operation was ongoing, and a relief operation centre has been set up at Chalong Bay.
The storm yesterday which caused waves of up to five metres high also overturned the yacht "Serenitta", throwing 42 of its passengers into the raging sea, with 40 of them rescued and two still missing.
The government of the eastern Chinese city of Haining in Zhejiang province said on its official microblog account that it received a distress alert sent by phone text message from the head of the Haining Haipai Furniture Co.
Thai Youth Soccer Team Found Alive, Hungry After 9 Days in Cave
The Tham Luang-Khun Nam Nang Non Cave complex is a popular tourist site, but often floods during the June-October rainy season. The boys, who range in age from 11 to 16 years old and are part of the same soccer team, have been missing for nine days .
Many tour operators have complained about lax enforcement when it comes to basic safety measures, including seatbelts in cars and lifejackets on boats.
Thursday's storms had forced 12 boats with 263 passengers in all to stay docked at Racha island, a popular diving spot about an hour's boat ride from Phuket.
The accidents came as rescuers, also led by Thai navy divers, support 12 boys and their soccer coach stranded almost two weeks inside a flooded cave in the country's far north, and try to determine how and when to extract them.
Chinese tourists make up the biggest foreign visitors to Thailand, with numbers surging in recent years due to the increasing popularity of Thailand's islands and cosmopolitan.
Some 48 people passengers and crew were rescued from the Phoenix before the operation was suspended overnight.
The Phoenix was among several boats that appeared to have ignored a severe weather warning in place since Wednesday to take tourists on day trips to the islands that dot the seas off Phuket.
Meanwhile, Deputy Prime Minister Prawit Wongsuwon has ordered an investigation into why "the boat went to sea" despite a weather warning of strong wind, according to an AFP report.