I am considering taking a job with the company who saying that I must be eligible for a work permit.

I entered Thailand a little over two years ago and have extended my stay twice based on retirement. If I decide to take this job would I need to leave Thailand and get a new visa or can transfer my stay in country?

Thanks

It would depend on the immigration office, but it is likely you will be required to apply for a non-B visa abroad first. Doesn't hurt to try to change the reason of your stay first. They might do it.

(You don't transfer, but change the reason of stay).

Likely you will initially need to obtain Non-B visa from embassy/consulate abroad, but have been some instances of immigration offices doing the 'switch' in extension status. You can try.

I am considering taking a job with the company who saying that I must be eligible for a work permit.

I entered Thailand a little over two years ago and have extended my stay twice based on retirement. If I decide to take this job would I need to leave Thailand and get a new visa or can transfer my stay in country?

Thanks

No work permit with Retirement Extension... However, if you are married to a Thai, you can change to Marriage extension and apply for a work permit.