Can I enter Thailand for 30 days without a visa and then apply for a tourist visa for 60 days?

No of course not. If you go without a visa there's the extension you can get but you cannot then get visas in country that have the same travel purpose as your exemption.

Probably best to get a visa before going.

Get a visa to start with.

When going to Thailand for 31 - 60 ( 90 )days, the 60 days touristvisa is the best option.

It is cheaper than visa excempt + 30 days extension.

No need of a onward ticket ( 90 days 1 onward ), if returnticket within 60 days.

It is easier to apply from the comfort of your home.

thaievisa.go.th

Not wasting holiday time to find, go to and waiting at a immigration office ( 90 you would need that ).

Then no need to leave Thailand in up to 90 days.

Also visit the website of your nearest Thai Embassy, could make it much easier to apply online

No, you cannot get a tourist visa in Thailand. You can only get a tourist visa at a Thai embassy outside of Thailand. It's all done online at most countries, so why don't you just do it before you travel? It costs less than applying for an extension inside the country anyways.

If you arrive without a visa you will only receive a 30 day stamp and can only receive a single 30-day extension before you will have to leave. To get 5 months you would have to leave and return at least twice.

If you arrive with a tourist visa and get 60 days, and apply for the 30-day extension, you only have to leave and return once to get 5 months.