Data roaming occurs whenever your phone disconnects from your carrier's network and hops on another network. Roaming allows you to make calls, send texts, and use wireless data even when you're outside of your network's boundaries. ... If you have the roaming feature turned on, all of this will happen automatically.

Do I want data roaming on or off?

If you really want to be safe, I recommend turning off Cellular Data entirely when you're traveling abroad. You'll still be able to send photos and check your email when you're on Wi-Fi, and you won't be surprised by a massive phone bill when you get home.

What does it mean when data roaming is on?

The real definition is simple: data roaming refers to scenarios in which you're still able to make and receive voice calls, send and receive data or access other services while outside your primary network coverage. Anytime your mobile device is connected to a non-Verizon Wireless network, that's roaming.