Data roaming refers to the ability to use your mobile device to access the internet while traveling outside your home network's coverage area. When you roam, your device connects to a different carrier's network, allowing you to send emails, browse the web, and use apps just like you would at home. However, data roaming can lead to additional charges, as international or out-of-network usage often incurs higher fees. It's important to check with your mobile service provider about their data roaming policies and any available international plans to avoid unexpected costs while traveling.