Hi, my three months NON O visa expires on next 10 October, if I will go to Savannaket for the multiple entry next week, I lose months?

Thank you

Your in the wrong forum, perhaps a Moderator will be along to move it. This current entry will be finished when exiting the country, and you will begin a new 90 day entry when entering with the multi-entry. So, yes, you will lose time on this entry.

Ok, many thanks

Moved to the Thai visas forum.

As said you will loose the days left on your current 90 day entry.

I think I would wait until I was a bit closer to the date the 90 days end.