Yes. You can record data on the Frontier X2 without connecting the device to the mobile app. The X2 is equipped with a memory chip, unlike most other devices on the market. This ensures that even if you don't connect it to your phone during your workout, or choose to connect it to an external device like Garmin, there's zero data loss as you can come back home and connect the Frontier X2 to the phone later. Once synced, all metrics recorded on the device will be accessible.