How can I extend my Thai visa using a marriage certificate?

My advice is to get a Multiple Entry Non-O Visa based on being married to a Thai woman at the end of your extension. To do this:

You'll need the following:

1. Original Wedding Certificate (the rose border one)

2. Copy of the front an back of the wedding certificate on a single page, signed by the wife and by you.

3. Copy of the wife's ID, front and back page, signed by the wife.

4. Copy of the wife's blue book with the address and name page, signed by wife.

5. Copy of my ID passport page, signed by me

6. 2 Passport Size pictures (for the Thai visa)

7. 5,000THB for the visa fee.

Arrive at the consulate in the morning, around 8am. Fill out the visa application, put it on top of the copies of the documents, and give it to the officer behind the counter. He'll want to see the original marriage certificate, and he'll give it back to you. You'll give him the 5,000THB, and you'll pick it up the next day in the afternoon at around 2pm. Don't try to talk, or explain yourself, just hand over the documents. If used correctly, you'll be able to get 15 months out of it, plus another 2 months on an extension of stay.

People who like to stay longer than the total of 90 days you got.

Then you can make another border run and get the 60 days Extension again. After that flying in and out as border runs are limited to 2 a calendar year.

With the 1 year visa people make border runs every 90 days and get almost 17 months of stay out of this visa.

Others apply for an 1 year Extension of Stay after getting this visa and do not have to leave the country.