What do I need to extend my tourist visa by 30 days at Jomtien Immigration?

To extend your tourist visa by 30 days at Jomtien Immigration, you'll need a copy of your passport, your 60-day visa, your entry stamp, a filled form from immigration, payment of 1900 baht, and potentially a copy of the TM6 and TM30 forms. It is also recommended to bring a passport-sized photo. While a return flight ticket is often required for other visa applications, it may not be necessary for the extension itself, but it's best to check beforehand. The extended visa is generally issued at the immigration office the same day, but it's advisable to visit closer to the expiry date of your current visa.