Can I apply for a 30-day extension immediately after entering Thailand on a 60-day visa exemption?

When applying for a 30-day extension after entering Thailand on a 60-day visa exemption, it's generally advisable to wait until you have about 30 days remaining on your initial visa. Some immigration offices may allow applications up to 45 days prior to the expiration, but many, like those in Jomtien and Samui, require you to wait until there are only 7 days left.