Visa on Arrival (VOA) cannot be extended in Thailand. However, if you are on a visa-exempt entry, it can be extended at the immigration office in Koh Samui, for a fee of 1,900 baht. You can visit the immigration office located on Soi 1, where facilities such as a restaurant are available for visitors.
I went to the immigration office on soi 1 on the north side. It was a few block from my bungalow. They have a restaurant outside. You can have a beer while waiting for your number.
Steve Cole. A VOA you buy at the airport when you arrive, it is valid for 15 days. A visa-exempt is a concession for about 70 countries where you are stamped in for 30 days without a visa when you arrive.
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