I have a tourist visa that expires on 23 June 2011. I want to know if I can enter thailand from a land crossing and still activate the visa ON the 23rd of June, or if I must enter on the 22 June in order for the visa to be accepted.

Am I right in thinking you have a double entry TV and the enter before date is 23/06/11...if this is the case than you must enter on the 22/06/11 or before...if you enter on the 23/06/11 you will only get 15 days....

It's really at the discretion of the immigration officer at the border. The only 100% safe answer is to enter before the visa expiration date.

Troll post removed.

Current policy seems to be to allow use of visa on expiration date but as said, safe thing is to do it a day early.