Naresuan-class frigate

The Naresuan-class frigate is an enlarged modified version of the Chinese-made Type 053 frigate with Western weaponry, cooperatively designed by the Royal Thai Navy and China but built by the China State [Shipbuilding Corporation] in Shanghai. The ships came at 2 billion baht each, less than the 8 billion baht claimed price tag for Western-built frigates.
Upon delivery, the Royal Thai Navy complained of the poor quality of the ships. The damage control system was very limited, with very basic fire suppression systems. It was claimed that if the ships’ hulls were breached, they would quickly be lost to flooding. The Thai Navy had to spend considerable time and effort to correct these issues.

Upgrade

On 3 June 2011, Saab announced that it was awarded a contract for the upgrading of the two Naresuan-class frigates. The scope of the upgrade will include Saab's 9LV MK4 combat management system, Sea Giraffe AMB, CEROS 200 fire control radar, EOS 500 electro-optics system and data link systems for communications with the newly acquired Royal Thai Air Force Erieye surveillance aircraft.
The ships also received 8 Mk 41 VLS cells in 2013, giving them the ability to launch RIM-162 ESSM surface-to-air missiles, greatly improving their anti-air capabilities.