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Navionics Boating: Deleting Downloaded Maps
Downloaded maps are stored in your device memory during an active subscription for use offline when an internet connection is not available.
You can delete mapping detail for areas you are no longer using to free up space on your device. Go to Menu > Delete Maps. You will receive a selection box as you would for downloading maps, which you can adjust before tapping delete to remove the charts. You will be asked to confirm the deletion of the maps.