Not all devices have data roaming automatically activated so you may need to active this yourself, through the relevant section on your device settings.
If data roaming is ON, and yet you still cannot use mobile data whilst abroad, you will need to check whether you are connected to the correct service provider. GO has agreement with select operators abroad. You can check our supported providers by clicking here and searching for the country which you are roaming in.
If you are still experiencing issues with connecting to a network, please speak to us via Live Chat or Facebook, so that we can help you with your connectivity.