I have the impression that it is possible to book a time to submit re-entry permit applications at Jaeng Wattana. The Immigration App offers Notification of  staying longer than 90  days, Contact us, which offers connections to various desks and general enquiries which is Musak for three minutes, (probably longer if one is prepared to listen), and News. 

Is it possible to book an appointment and if so how is it done? 

See https://extranet.immigration.go.th/qrepsonline/online/queue/REPSAction.do?cmd=term

True but if not using internet explorer you cannot even open the site. You get this message.

Click ok and the tab closes.

If using other browsers you could install the IE tab extension. See: https://www.ietab.net/

 

OP, very simple process at Bangkok airports on way out. Why make a trip to CW just to obtain reentry permit.

I want to be sure not to miss the flight or lose my extension. I have got one once years ago at the airport and checked last year, I agree that it is easy but I feel more comfortable being prepared. 

Thanks chaps, There is Explorer in the house I shall try that. 

7 minutes ago, tgeezer said:

I want to be sure not to miss the flight or lose my extension. I have got one once years ago at the airport and checked last year, I agree that it is easy but I feel more comfortable being prepared. 

Fair enough, but I fly every second week out of DMK and always glance as I walk past reentry/overstay office. I hardly ever see anyone there. It takes 5 mins. Take along form filled in with photo etc job done.