renting atv's?

You can do this on Koh Tao no problem. I am not too sure of the rest of Thailand. I know I saw some for rent on Samui also but I don't recall seeing people driving them on the roads.

I saw them on Ko Samet na Ko Samui too.

Ko Pha Ngan too, many more on the roads in 2007 than in 2006. With more supply, the prices should start coming down - when I was last there in July, rental costs were around 800-1000 baht per day, compared with 400 baht for a decent 250cc motorbike, and 100-200 baht for a small motorbike.

I believe that it's technically illegal to ride them on the roads, even though they are available for hire at the roadside, so you might want to bear this in mind!

You can rent them, but they are not allowed on the roads.

thank you so much guys for your swift replies

much appreciated