How can I extend my Non-O visa based on marriage in Thailand with an Indian passport?

To extend your Non-O visa based on marriage, visit the local immigration office to obtain the requirements. You'll need to provide documentation that includes meeting the financial criteria, which is either having 400,000 baht in a Thai bank account for at least two months prior to applying or a letter from your consulate verifying an income of 40,000 baht. You can apply for the one-year extension starting 30 days before your current visa's expiration date.