Three Indonesian fishing boats were seized and the 40 crewmen arrested after they were caught fishing in Thai territorial waters west of Phuket on Sunday.
R/Adm Puchong Rodnikorn, deputy commander of the 3rd Naval Area, said HTMS Klaeng was sent to investigate after a reconnaissance plane spotted three fishing boats operating west of Phuket on Saturday.
On Sunday, the navy vessel found the three trawlers - KM Rahmat Jaya (with 12 crew), KM Ikhlasbaru (16 crew) and the Kambiastar (12 crew) - 75.8 nautical miles west of Laem Prom Thep.
The three boats and their crews arrived under escort at Ratsada boat pier in Phuket on Monday. The crewmen were handed over to Chalong police for legal proceedings.