Navy commander Adm Narong Pipattanasai had ordered the search to stop on Saturday after Malaysian Prime Minister Najib Razak confirmed that flight MH370 had changed its course to a new destination, including Kazakhstan and the southern part of the Indian Ocean, the spokesman said.
But the navy still directed four ships - HTMS Pattani, HTMS Tapi, HTMS Songkhla and HTMS Sattahip - to stand ready in case the Malaysian government needs help for another search, said Rear Adm Karn.
The navy launched its operation to find the missing aircraft on Monday at the request of Kuala Lumpur.
Navy Region 2 combed the Gulf of Thailand and Navy Region 3 operated in the Andaman Sea. They deployed Super Lynx helicopters, soldiers from the elite Special Warfare Command, divers and patrol planes to join the naval fleets.
The air force said on Saturday that its radar system did not detect the plane after the new information indicated that it could have passed over the northern part of the country.
"Our most updated information in the radar system was in Hat Yai where the air force detected MH370 flying out of Kuala Lumpur in Malaysia. That was the first and last time we detected MH370," air force spokesman AM Monthon Sutchukorn said.
If a plane with no prior notification and without authorisation enters Thai airspace, air traffic controllers of Aeronautical Radio of Thailand have to alert the air force, he said.
The air force also has its own radar system to detect planes entering Thailand without permission having been requested, he added.