Only one jet ski was involved in the accident which claimed the lives of the driver and his 7-year-old passenger at South Pattaya beach on Monday night, not two as initially believed, a marine official said.
The jet ski was hit by waves and overturned.
The driver drowned. He was not wearing his life jacket as he had given it to the boy to wear. The child was seriously injured and later died in hospital.
The owner has been fined 10,000 baht for operating an unlicensed jet ski, and another 10,000 baht for a second unlicensed jet ski that went out to help after the accident.
It had been widely reported that two jet skis had collided, that the driver of the second machine, a man of Indian appearance, had left the beach before police arrived and was being sought for questioning. This was later said to be incorrect.
The director of the Pattaya marine office said on Tuesday afternoon that an initial investigation found there was no second jet ski involved.
An employee took the jet ski out to give the young boy a 15 minute ride, charging 500 baht. The boy sat in front of the driver. The jet ski hit waves and overturned, leading to the death of the driver, who was not wearing a life jacket at the time. The boy was thrown into the sea and received fatal injuries.
Another jet ski belonging to the same operator went out to help.
Police were initially told, about 7pm, that two jet skis had collided in the sea off the south end of Pattaya beach, near Walking Street.
Witnesses said there was a second jet ski involved, that the driver was of Indian appearance and had walked away from the scene after the collision and disappeared.
The Marine Department confirmed on Tuesday afternoon that a man was being questioned about the accident. This man was later confirmed to be the jet ski owner. No second jet ski or driver was involved.