to confirm and clarify...since I could not make a visa in Thai embassy this time...

Entering Thailand at Don Muang airport, I'm elligible to receive an exemption 30-day tourist visa (Israel passport). I understand I can get an extension of 30 days for 1900 Baht at Immigration offices anywhere.

1. Can the extension be gotten at the airport when I arrive or does it need to be close to the end of the 30 day period?

2. After the 30-day extension, if I leave and enter by land (Myanmar or Laos) and return by land, do I get 30 days on entry again ? Or 15 days? Is it dependent on my nationality?

3. Is a land border entry also extendable for 30 days?