Marriage License for married to Thai

Will an American marriage license translated into Thai language by an approved translator work for getting a one year extension

No, you need to then take that translation to an Amphur office and get the Thai marriage license issued.

You mean a marriage certificate?

Speak with an agent, quite a few around Chaeng Wattana that will give you exact information. Documents from your home country will need to be officially translated and stamped by the MFA. There are also specific time frames, think you have around 3 weeks to get everything translated and stamped.

I just did it.
What Aging One said.
You need to take thei translated certificate and go to the Amphur . You will need witnesses , so take a couple of friends or neighbors with you, or ask your local Amphure if they need Witnesses , some amphors might not TIT.

We just did it a few months ago when I did my extension based on marriage and did not know about the witnesses so we showed up without them, The lady at the office was very nice and found us some.
It pays to be pleasant to people . they tend to be pleasant right back .:)

Thanks for the info guys

recently when authorising some marriage related paperwork at the amphur office in khlong toey, we were required to produce a witness.

the government officers that work there are not allowed to act as witnesses so they dragged in the toothless old geezer that sweeps up leaves in the car park and he became the witness.

i think he was glad to spend 5 minutes in the air conditioning and we gave him 100b for his help.