It's cheaper and uses far less pages in your passport. I live a fair way away from a border crossing so getting the extension saves me a full day return journey to the border.
Yes you can extend any entry stamp for 60 days based on having a Thai Child. If you are married some offices insist on extending based on your wife. I go to Korat immigration and they accept me extending based on my son or my wife if she is available to go to the office.
You go to your local Immi office with your Thai wife and ask for a 60 day extension to visit your wife. Cost is 1900 THB. You need original Marriage certificate and a copy. Also copies of your wife's I'D card and Tabien Bahn.
you can extend each 90 day entry on a Multi entry Non Imm O Visa by 60 days at your local Immigration office if you have a Thai wife or child. So you can get 450 days and only need to exit Thailand twice after your initial 90 day entry.
You can extend each 90 day entry to Thailand for 60 days based on marriage at your local Immi office. So you can effectively get 450 days out of a 12 month Visa.
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