Hi,
I would think that if you have already purchased on eBay or directly from someone in Thailand that a Phytosanitary Cert. should or would have been supplied by the sender of the seeds. If you where to apply for anything it would have been a small quantity seed import permit.
I do not believe that most are receiving one of these.
Your seeds should arrive without an issue.
Rick

Thanks for replying, Rick! Hopefully they'll arrive safely

Josette

I've ordered seeds from Thailand and have never needed to apply for anything. I do have a small seed import permit from the USDA/APHIS but have never even botherd with it when ordering seeds from Thailand. You shouldn't have a problem.