There are two requirements: 1. An LTE network must be commercially available to AT&T customers roaming in the visited country. 2. Your device must be LTE-capable and compatible with the frequency (band) over which LTE is deployed on the foreign network. If LTE is not available or your LTE device does not support the LTE frequency band(s) required, you will automatically attach to a network with the next fastest data speed, typically 3G. For more details Call us now: 1-855-820-1220