Nowadays many airports provide free WIFI for their customers. You can expect to use the free WIFi at Suvarnabhumi Airport or Bangkok Airport as well.
To use the free WIFI, it is very easy. Just find the network named “.@ AirportTrueFreeWiFi” and follow the steps to connect. Your username and password will be valid for 2 hours per day.
If you do not have the smartphone, tablet, or other equipment that can connect the WIFI, you can use the one of the 126 internet kiosks at the Passenger Hold Room to connect the internet. This service is for departing passengers.
Another option is to use the internet at The CAT Telecom shop which is located at Departure Hall, 4th floor, behind Row U. Well, this option is not free. You are expected to pay 100 baht for 20 minutes, 200 baht for 40 minutes, and 300 baht for an hour.
Besides, The CAT Telecom shop also sells telephone card at 100, 300, and 500 baht. Photocopying and printing can be done here too with the cost 10 baht per page.