Standard tourist visa upon arrival is normally valid for 30 days upon arrival to Thailand without prior application for the most of passport holders. Please consult a Thai embassy representative in your home country just to double-check. To extend your visa duration you have several options:
• 30 day extension of stay. You can apply at the local Samui Immigration office for a 1 week extension. This normally takes a few hours at the office and cots 1.900 Baht.
• Overstay and pay fine at departure. You can just pay a small fee of 500 Baht / per day of overstay when you are leaving the country. This procedure is pretty straightforward, and only requires a small amount of cash on hand. There is a special counter for that in every airport as it is a very common practice, so do not worry about it at all. Just save enough and have the cash ready at airport for the amount of days you have overstayed.• Apply for 90 day visa prior your departure. If you want to be totally flexible and stay longer the best option is to apply for this type of visa in your home country before you leave. Cost and processing times vary so please check in advance and follow procedures of your local Thai embassy.
• Fly out, Fly in. Arrange a flight out of Thailand and return, you will be granted another standard visa upon arrival valid for 30 days. Please note that flights form Samui can be expensive if booked last minute so for this option check and book well in advance.