Exchange controls are administered by the Bank of Thailand (BOT) on behalf of the Ministry of Finance.  Although certain transactions still require direct BOT approval, the BOT has delegated authority to approve many commercial transactions agents.
Most foreign exchange transactions can be processed though commercial banks.  For all foreign currency matters, currency inflows must be recorded, and contracts and legal documents must be documented.

Both residents and non-residents can open foreign currency deposit accounts (FCDs) at commercial banks following certain conditions; where said conditions are not satisfied, BOT approval may be required.
A non-resident can also open a non-resident baht account with commercial banks.

Useful Links:

• Link to Exchange Control Regulations, Bank of Thailand
• Link to Exchange Control, eThailand website