How early can I go to immigration in Bangkok and get a 30 day tourist visa extension?

 

I think you can do it up to 7 days before your 60 day entry stamp expires, but can't find anything in the search.

 

Edit:  Just found answer to one question of losing days by extending early.  Ubon Joe says you don't lose days.  The extension starts from the end of your 60 day entry.

Edited April 23, 20188 yr by asdfrules

You can apply about 2 weeks early at most offices.

Thank you Mr. Joe