You would need to first update your device's PRL and Data profile:
Make sure to be connected to the Wi-Fi.
- From the home screen, tap Phone.
- On the keypad, dial ##873283# and tap the Call button.
- Tap OK.
The handset will search for profile updates and install them.
- Tap OK.
- The PRL and Data Profile now updated.
Before departing, please make sure you set up your device for International use. You may follow these steps to Enable International Data/Voice Roaming :
1.From the home screen, tap Settings.
3.Ensure Cellular Data is enabled, and then tap Cellular Data Options.
5.Tap to enable Voice & Data Roaming.
*Note: This screen is not displayed if Voice & Data Roaming is already enabled. Continue to the next step.
6.Tap to enable Data Roaming and disable International CDMA.
7.The device is now configured for international data roaming
When you land in PRG, just turn on your device and accept pop up terms for Global Roaming. Calls will be $0.20 a minute and no charge for texts and unlimited 2G data. You can access LTE speeds for $5 for a 1-day data pass or $25 for a 7-day data pass.
Keep in mind that if you have the Open World option, rates are a little different......