Priaia Grande de Mino is a lovely white sand beach with dunes and the bay is sheltered there, so the waves are not big. You would not think that you were in Galicia.
The problem is the Ingles walks through the main street of Mino town and then out and the beach area is over a kilometre to the North. You would not know that you were in a seaside town unless you researched beforehand. You only see the sea when you climb up over the bridge over the railway and then you are on the cliffs, not the beach. That is why, if you have time, stop overnight at Mino. Pontedeume to Mino is a half day walk allowing you to walk to the sea, and swim in the afternoon. Then you can make a half day walk onto Betanzos to have proper time to explore this old city. If you walk, Pontedeume to Betanzos, this is a 7 hour walk minimum, and you have little time to stop and linger on the way.
Cabanas, the town the other side of the river to Pontedeume, also has a sandy beach backed by pine trees. It is not as picturesque as Mino, but like Mino, Cabanas is a holiday town in its own right, noting the shops on the main street selling inflatables, etc. Again, the problem is the Ingles has been rerouted at Vilar de Colo, so that instead of walking down to the beach at Cabanas and then along, the waymarks keep you inland and you come down the hill at Cabanas away from the beach, and again, unless you knew you would not know you were there. Once you have crossed the bridge to Pontedeume, you are tired and reluctant to walk back 1.5 km to Cabanas beach.
If you only have time to dip your toes in the water, en route, South of Mino, the Ingles does run next to a small beach at A Ponte do Porco where the river runs out to the sea. It is less swimmable there, but worth taking your shoes off and walking on the sand, and dipping your toes in the sea.
