How early can I apply for a 30-day extension on my visa exemption in Thailand?

Okay whether you DO or DON'T require a TM30 receipt to get your 30 day extension is totally up to the immigration office you use

So I don't care if you've gotten dozens of 30 day extensions without a TM30 receipt IF the office you're applying at requires it you aren't getting a 30 day extension from them without it 😕

This is the likely things you'll need to apply for a 30 day extension based on tourism

Thank you for the information

In Chiang Mai you can apply for an extension when you have 45 days or less left on your current stamp (so you're good going when ever you want to and won't lose any time going early because they add the extension to your existing stamp

You can use the main immigration office by the airport or the one in Central Festival Mall