What are the steps to apply for a Thai marriage visa for expats married to Thai citizens?

First attest your home country marriage from ministry of foreign affairs in your country second step attest it from royal thai embassy in your country then come to thailand go to your embassy and attest your home country marriage certificate from embassy also first page of the passport attest it from your embassy in babgkok then translate your home country marriage certificate and passport first page in Thai language and attest all documents from mofa Thailand then go to your local amphur with two witnesses and register your foreign marriage in Thailand and they issue you a kor ror 22 certificate

First check the requirements on the Thai embassy website in your home country. You then need to create an account and apply for the visa using that. You'll need to upload various documents. You don't have to complete the application straight away, you can save and complete later (normally within two weeks). There is an excellent User Guide that walks you through the entire process. They may request additional documents so just upload as required. You can follow the progress of your application via your account. The visa will be emailed to you as a pdf file that you print. You have three months to enter Thailand from the date the visa was issued. Foreign marriage certificates generally need to be certified by your embassy here then translated and legalized by Consular Services. Check before you arrive if there is anything you need to do regarding your marriage certificate in your home country, it can vary from country to country. When you arrive the priority is opening a bank account, depositing the required funds (unless your embassy provides income affidavits). Go to your local immigration office and get the handout of required documents to apply for your extension of stay, get everything together and after your money has seasoned for two months go and apply. It can be a bit of an adventure first time but if you're organized and patient you can navigate it yourself. Otherwise pay an agent some ridiculous amount to assist you. Good luck!

And maybe a tip, if not already done so, for later year extensions your marriage has to be registered in Thailand.

Mate very easy apply on Thai embassy web site evisa send them everything they ask for, don’t worry about making a mistake they will come back to you and ask for any missing or extra information they need, easy and straightforward, you should get it within 2 weeks

AI

Applying for a Non-O visa based on marriage is straightforward. You can apply electronically for a 90-day stay. After arrival, visit your local immigration office for the requirements. If your embassy doesn't provide an affidavit letter for income, you'll need to deposit 400K baht in a bank account 2 months prior. Don't forget to register your marriage in Thailand. Contact the Thai consulate for guidance on document preparation before you leave.