What are the steps and requirements for applying for a one-year extension of stay on a marriage visa in Thailand at Chaengwattana?

You can also book the queue online

I have placed the TOPIC of ...Extension Married to Thai

AND

...CW Immigration office

on your Post

CLICK on them and all posts about getting the one year extension of stay as Married to Thai will pop up to read.

You should head on out to Chaengwattana with your wife and get the hand out from section L-1 listing the requirements for the yearly extension based on marriage to a thai

it's my direct experience that most of the "long and painful" parts of the process can be eliminated by doing that.

That way you know the documentation, copies, photos, etc they want and can go prepared rather than try multiple times to get it done.

Remember in Bangkok you can apply when you have 45 days or less left on that 90 day non-O stamp so no need to burn it down to the last few days, you don't lose any days applying early the year extension is added to your expiration date now.

This is a general idea of what can be required for an extension based on marriage it is NOT immigration office specific which is why I said slog on out and get the hand out yourself.