Can I get a 30-day visa exempt entry by crossing to Penang and returning to Thailand?

As you are the manager of "One Yoga Thailand", (as shown all over your profile). Why don't you get the correct visa and work permit?

@Cla***

It is your use of wrong terminology that's messing up the answers to your question(s)..

As people correctly stated there is NO such thing as a 30 day visa on arrival :/

There is however a 30 day visa exempt entry :) which people from 51 countries (ireland included) get when they enter thailand without having bought a visa from a thai consulate before hand.

You are limited to TWO 30 day visa exempt entries per year by land.

Also be advised those southern land border crossing officers can be finicky and ask to see 20K baht in cash.

There is no 30 day visa on arrival. Countries on the specified list can get a 14 day visa on arrival. I suspect that you got a 30 day visa exempt entry when you arrived.

yes you can as you described. Extension of a 30 day visa exempt will be 1900 Thai Baht at any immigration

Also be aware that you can only do two land border crossings a calendar year if you use the Visa Exempt Entry method.

Why you not apply for the Single Entry Tourist Visa while your are in Penang and get 60 days of stay on return into Thailand. But you can do as you wrote, only thing is it is not a Visa on Arrival but called a Visa Exempt Stamp. Also be aware that the border check point ask many people to show the 20.000 Thb or equivalent currency in cash.