A friend of mine's entry permission ends on the 1st, but he is considering departing on the 2nd, by air from either Phuket or Bangkok. Would this result in an overstay stamp?

There would be a stamp for overstay done. A one day overstay stamp is nothing to be worried about though.

In Phuket he would probably pay a 500 baht fine when leaving. In Bangkok he would not be charged the 500 baht fine and the stamp would state he overstayed less than 24 hours..

Thanks, he really would not like the stamp, so that means he might go to Ranong for a quick exit and entry tomorrow. No issues there with out-in at the moment?

Thanks, he really would not like the stamp, so that means he might go to Ranong for a quick exit and entry tomorrow. No issues there with out-in at the moment?

He could also apply for a 7 day extension at immigration and after paying the 1900 baht fee be given 7 days to leave the country.

Thanks, he really would not like the stamp, so that means he might go to Ranong for a quick exit and entry tomorrow. No issues there with out-in at the moment?

He could also apply for a 7 day extension at immigration and after paying the 1900 baht fee be given 7 days to leave the country.

Yes, but Ranong from Phuket can be a nice trip, stay overnight in the area and having a good time.

Thanks.