Yes, it is legal in Thailand. Thai based bitcoin exchanges can solely exchange Digital Currencies for Thai Baht and are required to function with a Thailand Business Development Department e-commerce license. They are additionally required to have KYC and CDD policies and procedures in place, in accordance with the Ministerial Regulation Prescribing Rules and Procedures for Customer Due Diligence, Reference Page 8 Volume 129 Part 44 A Government Gazette 23 May 2555 (2012).

Suspicious undertaking must be reported to the Anti-Money Laundering Office (Thailand) (AMLO), of Thailand.