I have a multiple entry non-o visa from KL (for marriage) and my 4th stamp expires in 2 weeks. I just picked up my new passport yesterday at the US Embassy. The guy at the US Embassy gave me my new passport, my old passport (stamped cancelled), and a letter requesting transfer of the stamp. Seemed pretty simple to me.

Then I went to Thai Immigration...

At the Thai immigration office (Government Center Chaeng Wattana Building B ), after getting needed copies and form, we went to get a queue number. The guy had to check our paperwork before giving us a queue number. He fumbled around for a bit until he turned to his buddy and asked him a few things. His buddy figured out that he was looking at the wrong visa. So with some more fumbling and questions, they finally determined that I need to present both passports to get a stamp. I am assuming that they mean, go to the border and show both passports to get the latest entry stamp.

So, what am I REALLY supposed to do? Any advice?

Thanks.

It used to be you did at Immigration but now they only require that for those on extensions of stay it seems (no notice given that I am aware of). So now the procedure seems to be to present both passports when you exit and required stamps will be entered then. If you have a valid visa (multi entry that has not expired) you can still use that to enter on return but must present both passports and arrival stamp will be in the new passport.

baaaahhh. This is scary, reading this.

My single entry tourist visa (60+30) expires next Tuesday. I JUST got my passport back from Canada because it was about to expire and I need to transfer my stamps from my old passport to the new one. Canadian embassy said it would be no problem. They didn't give me a letter, but they gave me a receipt? I have booked a 3 day tourist visa run to Laos for next Monday to get a double entry, but if they don't transfer over the stamps, is it still going to work? I'm nervous now....

Immigration will transfer the details of your old passport to your new passport, including your entry. that is in your case normally done at the border. With that you are set to use your new paspsort. As you don't have a valid visa, unlike the OP, you only need your new passport after the details have been transferred. Immigration stamps you out in the new paspsort and you enter Laos with the new passport and apply for a new tourist visa.

Immigration will transfer the details of your old passport to your new passport, including your entry. that is in your case normally done at the border. With that you are set to use your new paspsort. As you don't have a valid visa, unlike the OP, you only need your new passport after the details have been transferred. Immigration stamps you out in the new paspsort and you enter Laos with the new passport and apply for a new tourist visa.

I wold like to transfer my retirement visa from my British passport to my NZ one. Reason being my UK one expires soon and I have some years to go on my NZ

Immigration will transfer the details of your old passport to your new passport, including your entry. that is in your case normally done at the border. With that you are set to use your new paspsort. As you don't have a valid visa, unlike the OP, you only need your new passport after the details have been transferred. Immigration stamps you out in the new paspsort and you enter Laos with the new passport and apply for a new tourist visa.

I wold like to transfer my retirement visa from my British passport to my NZ one. Reason being my UK one expires soon and I have some years to go on my NZ

Visa or extension to stay from immigration?

I doubt that immigration will allow you to transfer a visa or an extension of stay between two passports of different countries. You can contact the immigration hotline at 1178 and ask them to be sure.

Getting a new British passport might be easier.