Menorca commonly has fantastic coverage on the beaches. In recent years, 5G and 4G networks have been present in the entire geography thanks to the antennas distributed throughout the island.
Both beaches are far from mobile antennas, and their orography is irregular. These are two beaches with no mobile coverage in Menorca.
It would be best if you did not worry; most of Menorca's beaches have coverage, which is excellent. Furthermore, 4G and 5G are present on the entire coastline.
If you want to relax on the beach and at the same time be aware of your mobile for any reason, try to go to the most accessible and connected beaches on the island.