National roaming allows mobile phone users to access cellular networks outside their primary service area. This means that if you travel to a different region where your carrier does not have coverage, you can still use your phone by connecting to another carrier's network. This service ensures that you stay connected even when you are away from home. Typically, national roaming agreements are established between different mobile network operators. These agreements enable users to make calls, send texts, and use data seamlessly, without needing to switch SIM cards or change settings. This is particularly useful for travelers and those living in rural areas where coverage may be limited.