DMM mobile is a free app for Android that allows users to insert their SIM cards into SIM-free smartphones and tablets to access the internet and make calls at a more affordable rate. Users can transfer their phone number when switching from their current mobile carrier to DMM mobile, making the transition easy. To use the app, a SIM-free device is required.

The app offers several features, including the ability to check high-speed data communication remaining amounts on a graph. Users can also purchase additional high-speed data communication amounts (100MB, 500MB, 1000MB) at any time and anywhere. The app allows users to turn high-speed data communication on or off depending on their needs, as well as view billing information for up to the past three months. Users can also set up notifications to receive email alerts when their high-speed data communication usage reaches 20% of their contracted plan.

DMM mobile recommends using the app on Android smartphones with version 5.0 or higher, 1GHz CPU, 1GB of memory, and 20MB of available storage. Please note that only DMM mobile members can use the app, and it may not function correctly on all devices. In case of any issues, users can try updating their Android System WebView or Chrome browser to the latest version.