How long does it take to receive a WP3 form after applying for a work permit in Thailand?

There is another document issued by the Labor Ministry that is required to be a part of the B Visa application package. The other document is a Cover Letter verifying the issuance of the WP. 3 stamped "Successful WP. 3 Application". This cover letter is signed by a Labor Ministry Officer and is often issued at the same time as the WP. 3 "Successful Application" copy is made available. But it can take 2-3-4-5 days before the Cover Letter is issued.

You can apply for the Non B visa without it then do WP1 when here but they may insist on WP3 its up to the consulate

Normally it gets handed out directly after all document are received and checked at the Ministry of Labor, should be max 10 minutes.