Since few months the regulation has changed but not been officially put in place.
The Land Department will accept to transfer the title deed in freehold ownership to the non-Thai even if the conversion into THB has not been done by the local Thai Bank receiving the money.
To do so, you will have to get from the Thai Bank the Credit note (one form given for each overseas transfer done).
Then your bank will have to issue the reference letter stipulating that this money was coming from overseas and stipulating the name of the buyer and the details of the condominium being purchased (project name, address, unit number, size of the unit).
Sample of Thai bank credit advice:
Sample of Thai bank reference letter for condominium purchase:
Note: Sometimes the local Thai bank receiving the money is not liable to issue the reference letter. It can be the liability of the foreign Bank having a branch in Thailand.
For example for a transfer from China to Thailand that has been done in THB.
The credit advice will be given by the Thai Bank receiving the money. The reference letter will have to be issued by the branch of Bank of China in Thailand. This is done by presenting the credit advice from the local Thai receiving Bank to the Bank of China branch in Thailand. (In this case this process is not immediate – it may takes up to 24 hours to receive the reference letter from the Bank of China).