What should I know about extending a TR60 visa in Thailand, particularly in Chiang Mai?

>is there an optimal date to extend? Does this need to be a certain duration before my current visa expires?

You can do it up to the last date. Chiang Mai, Bangkok, Buriram, Chiang Rai and a couple of others all allow people to apply for extensions when they have 45 days or less left on their current stamp. The other immigration offices are 30 days. However, ask your local immigration office for specific details.

> how long does the process usually take?

A few hours, depends on the length of the queue of course. The extension of stay is issued on the spot.

>will I need to show my revised return flight?

No. You will need the following:

1. Your passport and:

a. a copy of your data ("picture") page

b. a copy of your most recent visa (if you have one)

c. a copy of your most recent stamp

d. a copy of your departure card

2. A TM30, filed in the immigration office.

3. The forms (each immigration office may have different forms, and want to use their special forms)

4. 2x passport pictures

5. 1,900 THB.

You can do it whereever it gets added from the first stamp.

Chiang mai takes 2-3 hours faster if you are there when they open and have all papers and photo done.

No need for a return ticket.