How soon before my marriage visa expires can I apply for a one-year extension in Pattaya?

@Pete ******

Terary, this is the correct answer

Jomtein is 30 days remaining on your Non-O before you can apply for the extension of stay based on marriage. Just done mine.

Probably best to ask in Jomtien office. They have different rules than many offices. Most allow 30 days prior. Some 45 days prior. For short term extensions they usually only allow 7 days or less. No idea on their policy for long term extensions.