Do I Need to Leave Thailand to Switch from an Ed Visa to a Tourist Visa?

You have to go back out

No. You need to exit and re-enter.

You can then only get 7 days to leave contry for 1900bt

@Nicole ******************

, Immigrations cannot change your ED extension to a tourist visa.

You either go to a thai consulate and BUY a single entry tourist visa or bounce out and back in to get a 30 day visa exempt entry stamp (if you haven't gotten two 30 day visa exempt entry stamps by land this year).

They can't change it to a tourist visa, you would have to leave. Presuming you are on an extension off an original Ed visa, they will cancel your current extension at the date your school writes on the letter. This can be a bit of time in the future, to allow you time to sort yourself out and leave, however if it is cancelled on the same day you go to immigration, your choices are either to (1) leave immediately or (2) apply for an extension denied for 1,900B which gives you 7 days to leave.

Your best bet for a new tourist entry right now, presuming you are eligible, would be a land border bounce. They are less risk than airports and I'm presuming if you were on an Ed visa you have not used your two already this year, might as well use now as it resets Jan 1 anyway. This will give you 30 days you can extend by 30. Just note if you are from South Africa you may need to pick the border carefully, I have read that Kanchanaburi for example won't allow South Africans to bounce. A border like Nong Khai or Mae Sai should be OK.