In Gamagori there is an island, just off shore, housing a collection of old Shinto Shrines. It’s a small island, not even a mile across.
Besides the shrines, there are beaches around the outer edge of the island which are known for their shellfish.
After paying respects at the various shrines, it’s a quick walk back from the exit, though not necessarily and easy one.
There is an uneven path set between the hill the shrines are perched upon and the surrounding beaches. Some places are quite steep, especially for those wearing inappropriate shoes. The walk is only about 15 to 20 minutes, depending on how many pictures you stop to take or shells you decided to collect.
My friends and I took about 40 minutes for obvious reasons.