I've been working in Thailand for several years and will soon change jobs to work for a different company.

My current Non-Immigrant 'B' Multiple Entry business visa is good for re-entries through June 2015.

When I change jobs can I still use the same visa through June 2015, or does it expire because of leaving the employer that sponsored it (which would mean I would need a new Visa)?

Also what about my Work Permit, which is currently good through December? Will it expire as soon as I change jobs?

Thanks!

If you have a valid multiple entry visa from abroad it remains valid whn you stop working.

Your WP is another matter. it only allows you to work for the company named in the WP. if you stop working, the WP must be cancelled and you can apply fro a new WP with the new company.

are you sure its a multiple B visa and not an extension of stay for employment, as if its an extension, that is "revoked" your last working day

your WP will "expire" when you move jobs.

if a multiple B visa, you should be good, but if an extension of stay you may need a new visa.