The four-member rescue team used a rope to harness the dog and pulled him to safety.
The rig's crew came to the dog's rescue after they found her struggling to keep her head above water as she paddled through the ocean.
Boonrod was lifted by crane on to an oil vessel that was passing through the area on Sunday to be transported to a veterinary practice in southern Thailand.
The oil rig worker who saved the pooch said she is between 3 and 5 years old and now has "a lot of energy".
He said: "We found her trying to swim towards our rig, which is about 220 kilometers (136 miles) from the shore".
"We just saw her small head but if the ripples were bigger, I think we probably wouldn't have noticed her at all".
Video shows two of her rescuers lifting her onto the rig.
"Finally, we chose to tie a rope around his neck and pull him to our site", Vitisak wrote.
'When we first took her onboard her she was depressed and exhausted from being in the water for a long time. She had lost her body water. He looked "exhausted" but the workers gave him water and fed him some mineral supplements, Payalaw wrote. She started sitting up and walking normally'.
Animal charity volunteers who are now caring for the dog do not know if she has an owner or if she was a stray. It is unknown whether the dog swam the astonishing distance from the shore, or jumped off a boat at sea.
He was nursed back to health on the rig while staff radioed for help, requesting the assistance of a tanker that was heading back to shore. He was warmly greeted by animal lovers from Watchdog Thailand and veterinarians.
The dog was said to have been in good spirits when he arrived on land to be taken to the vet.