If you ask a travel agent about the presence of Wi-Fi in Thailand, you will answer with certainty, that Wi-Fi is everywhere! Indeed, in Thailand, in addition to hotels, Wi-Fi can be found in the internet cafe, the usual bars, mail and even on small islands. But! Internet in Thailand for an extra charge: the more expensive the hotel, the more expensive it will be Wi-Fi.
Even if you are willing to pay a certain sum of money, do not think that you will be able to work, because the speed of the Internet is not just slow, and very slow. You can pay for 2 hours of work and difficult to check the mail.