Hundreds of rescue workers waded through muddy swamp to pull charred bodies from the wreckage of the plane, which was carrying 146 passengers and crew.
They used heavy cutting equipment to open the fuselage of the A310-200 jet and recover the dead, including the remains of a pilot trapped in the cockpit, rescue officials said.
Police said at least 97 people were dead, some of whom were still inside the fuselage, which caught fire after the crash. Local television quoted other officials as confirming 94 dead.
The plane came down as it was trying to land at Surat Thani airport, on the mainland near the popular island holiday resort of Koh Samui, the airline officials said.
They said 46 injured had been taken to five local hospitals. They included 12 foreigners -- three Japanese, two Israelis, four Australians, two Germans and one Briton. Police said there were only 43 survivors, but gave no details.
Flight TG 261 from Bangkok to Surat Thani plunged into a flooded field at around 6.45 p.m. (1145 GMT) Friday, three km (two miles) from the airport.
Rescue workers from police, the military and private organizations battled through thick mud and chest-high flood waters in a steady drizzle and found the plane's flight recorder near the wreckage. Helicopters circled overhead.
The plane's broken wings were some distance from the fuselage which was split in two, with half stuck in water. Trees nearby were charred from flames that had enveloped the plane.
About 250 rescue workers sifted through smashed plane parts, life jackets, luggage and other debris floating in the water.
``It's very difficult work because of all the mud after the rain. The operation will continue till we find all the bodies. So far most of the bodies found trapped in the plane were strapped in seat belts,'' said Air Force Sergeant Komim Sinsomboon.
The head of the rescue operation, Police Major General Voraphot Intasee, said: ``The plane crashed into the water and then blew up. It's dreadful, dreadful.''
Survivors said the aircraft had made two attempts to land at Surat Thani before it crashed on the third attempt. Passengers had been told to prepare for an emergency.
Cabin crew member Kitti Tantiraksa said passengers started to panic as the plane made its last desperate attempt to land.
``People lost control of themselves and started shouting and screaming,'' he said from his hospital bed.
Israeli Limor Belafonte said many passengers were laughing, perhaps nervously, before the plane crashed.
``I was shaking,'' ``But everyone was laughing. But once it came down, everyone was screaming, crying and there was a lot of shouting.''
With local resources stretched to the limit, corpses were laid out on benches in the main waiting room at the hospital and hideously charred bodies lay on open ward trolleys.
At the airport, crash victims were loaded into body bags in full view of horrified passengers awaiting other flights.
The European Consortium Airbus Industrie said it was sending a team of experts from its Toulouse headquarters in southwest France to help in the crash inquiry.
Airbus spokesman Sean Lee said the company had ``absolutely no idea whatever'' what had caused the crash.
A senior international air crash investigator said bad weather appeared to be a likely cause of the accident, but pilot error could not be ruled out.
``It may well be it was the weather, but maybe the pilot stalled,'' said the investigator, who declined to be identified. He said it was ``a bit of a mystery'' why the pilot was unable to follow the landing aids located at the airfield.
Airport officials said the landing aid equipment at Surat Thani had been ``operating perfectly'' Friday.
Airbus said the plane had General Electric engines and was delivered in April 1986. It had logged 23,000 flight hours.
The dead included a member of parliament for the ruling Democrat Party, Thawat Vichaidith, a senator and a sister of the Thai Transport Minister Suthep Thaugsuban.