It is located directly opposite the tiny hamlet of Sandycove (population around 100) and no more than 200 meters (656 ft) off the shore.
The island is uninhabited except for a herd of feral goats which has grazed on the island for generations, an indication that there is probably a reliable source of fresh water on the island. Over the centuries a number of ships have foundered on the rocks off the island, including the 147-ton brig Eliza which went aground on the island in 1826.
The Sandycove Island Challenge is an open water swimming race held annually since 1994. The course is from the slipway at Sandycove on the mainland, around Sandycove Island and back to the slipway. The total distance is approximately 1.6 km. If sea conditions are unsuitable on the day, a more sheltered course is followed.