In the past I was able to make an online appointment to go to HH immigration and renew my retirement extension without issues. But now I do not see any way to schedule appointments for the Hua Hin office. Would appreciate any information. Thanks. 

Did the appointments actually work ?  Never scheduled one, as 100 kms away and didn't want to misjudge my arrival time.   

 

Did ask once if they were honored, and IO told me 'not to bother', taken that as a cue, to not bothered to test.   Usually there less than one hour during extensions, so quite tolerable.  Just save my internet reading till arriving, and time passes quickly.

I made two appointments in the past and they were right on time no waiting. 

OP, here is thread and in first post I posted link to appointment.

I just tried to make appointment and seems to work.

Only concern is all slots were available which is not normal.

 

The thread also points out that process time not too bad unlike eg CW.

 

https://aseannow.com/topic/1333181-link-for-online-appointment-booking-for-hua-hin-immigration/