Do I need to transfer the DTV visa entry stamp to a new passport after renewal?

I did this a few days ago. At immigration exiting Bangkok I showed my old passport (as listed on the DTV) but they wanted to se my new passport. They stamped and wrote something in my new passport. Entering back into Bangkok the next day the IO said I just need my new passport now as it’s been noted on the system, but I’ll always travel with both just in case.

No. Just keep your old passport and show it the IO when you leave Thailand.

Not in Jomtien. Immigration told me they don't do it here, and to deal with it at the airport

Yes, you should. It actually made things more complicated when I did it because there wasn’t much clear information available. I entered through Bangkok, so I assumed I had to go to Bangkok Immigration for the stamp transfer but that’s not the case. You need to go to the immigration office in the place where you live. So if you live in Chiang Mai, you should do it there. The requied documents are simple:

- your old passport original/copy

- your new passport original/copy

- TM30

- visa pages

- DTV visa print

I think that’s everything. The process in Chiang Mai was simple and quick. In Bangkok, though, you’ll need to arrive a bit early, get a queue number, and then follow their process.

Keep us posted how it goes, I will have to do the same soon

Yes I suspect so.

Interested to learn how / where you do this

You will use your new passport to stamp in or out of Thailand, You'll also need to carry your old and new passports and print out of your DTV when entering.

yes