After Vietnam, Thailand was the second nation in South East Asia to receive Freedom Fighters, although the first aircraft actually arrived in Thailand in 1966 before the SVNAF had declared its F-5s operational. Thailand received its F-5s as part of an agreement in which Thailand would allow American forces to be stationed on its soil.
Thailand ultimately received 24 F-5As, four RF-5As, and two F-5Bs. In Royal Thai Air Force service, the F-5A has been given the designation B.Kh 18. The planes were all based at Don Maung AB, with the F-5As being allocated to 13 Squadron and the RF-5As to 11 Squadron. No 13 Squadron later relocated to Nakhom Ratchisima (formerly the old USAF base at Korat) and became 103 Squadron.
By the early 1980s, attrition had reduced the number of F-5s to 14. Only a few of these remain in use, although two extra F-5Bs were acquired from Malaysia in 1981. They have been supplemented by F-5Es and then by F-16s. 103 Squadron began to take delivery of the F-16 in 1988, transferring its F-5s to 231 Squadron in 1989.