Is the one-year extension for a Non-O visa a multiple entry visa?

The one-year extension on a Non-O visa for a Thai wife is not multiple-entry by default. You need to apply separately for a multiple-entry re-entry permit at immigration, which costs 3,800 baht. It is advisable to do this when applying for the extension to avoid additional trips to immigration or issues when traveling. There are also options for a single-entry re-entry permit for 1,000 baht if you don't travel frequently.