One of the most unpleasant surprises for travelers is the sticker shock from their cell phone bills when they return home.

To avoid this, turn off data roaming when traveling outside the U.S. or switch to airplane mode to eliminate all data usage. Only connect for calls or check emails or texts when you have access to Wi-Fi.

You can also buy an international data roaming plan. AT&T offers plans for $10 a day. But be warned: the costs can quickly add up with caps on gigabytes. It’s often better to wait until you’re back at your hotel and connected to Wi-Fi.