How to connect to free wifi at Sao Paulo Guarulhos Interntational Airport (GRU)
There is free Wifi for all travellers for the first one hour you are at GRU. After your hour elapses you can purchase an hourly or monthly plan. Also within the first hour you can upgrade to premium wifi in case you want WiFi with faster speed.
Connect to the wireless network: GRU- wifi
Launch your browser and log into your existing account. In case you don't have an account, sign up for a boingo account.
There is free wifi and computers at the American express lounge on terminal 3 in the VIP lounges area.
The lounge however is only available to international flight passengers only and you must have a gold card. I'm not sure if they accept normal green cards.