If you have had your wedding ceremony in Thailand you now need to register the wedding in Thailand. The very same goes with an Islamic wedding in Thailand. Both Christian, Islamic and Buddhist weddings are not valid in according with Thai and Australian law until it has been registered with the District Office in Thailand.
See the other page on this website about an Islamic marriage in Thailand and its process before you register your marriage in Thailand. Once you have completed the ceremony the wedding needs to be registered. This starts at the Australian Embassy in Bangkok or at your Embassy in Bangkok if you are not Australian. You have to complete a form at the Embassy and hand this back to the Embassy official. If you have been divorced you also need to give them a copy of the divorce decree and also a death certificate if you a wife had died. The cost of this ‘letter of no impediment’ or ‘letter of affirmation’ depends on your Embassy. Some take 3 weeks while with most it tends to be an overnight process. The costs of this also vary greatly.
Once you have your letter in hand you now need to take your letter down to the Thai Department of Foreign Affairs in Laksi and they will then take a few hours to verify the authenticity of the letter. If you go early you should be out of there by the late afternoon. They have to verify the letter and the signature on the letter with the Embassy. They will stamp the letter to show that it has been verified.
With the letter of no impediment and also the stamped version from Foreign Affairs you now need to go to an Amphurs offices or District Office in Thailand to register the wedding. You need to complete a form for this and provide all the needed documents. This should not take more than an hour to complete. You Thai wife will have to go with you as they need to see both parties present to complete and sign the forms. Note that if you wife had changed her surname they will also ask for a name change certificate so best to take that along as well as her Thai ID card and Tabian Baan.
The process of marriage registration is not very complex but it drags on for days. When you add in the usual government and Embassy bureaucracy it becomes frustrating and tiresome. Most expats and foreigners simply drop off all their documents with a lawyer and return 10 days later to collect their marriage certificate. Their costs offset transportation to and fro and all the usual queue standing and getting all the documents into the correct order.
Take it from me you would be better off letting someone else get the grey hairs in Asia.