Thailand may build a new OPV in 2022.

According to information published by Defense Studies on April 15, 2021, for the fiscal year of 2022, the Royal Thai Navy may be able to supply a new offshore patrol vessel or OPV, priced at 6.5 billion baht.
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Krabi-class HTMS Prachuap Khiri Khan (Picture source: Thai Military and Asian Region)

Royal Thai Navy already has two Offshore Patrol Vessels, HTMS Krabi (551) and HTMS Prachuap Khiri Khan (552).

The Krabi-class Offshore Patrol Vessels are 295 feet (90 meters) long with an overall beam of 44 ft (13.5m). The vessels can reach a maximum speed of 25 knots and operate out to 3,500 nautical miles when cruising at 15kts.

The vessels are armed with an Oto Melara 76/62mm Super Rapid naval gun on its foredeck, two MSI 30mm gun mounts, as well as two M2 12.7mm heavy machine guns.