Sunayama Beach, Coastal beach in Miyakojima, Japan.

Sunayama Beach is a white-sand beach on the west coast of Miyakojima, Okinawa Prefecture, Japan. It lies beyond a sand-covered hill, or sunayama, from which it takes its name. The beach is short, and a natural rock arch formed by wave erosion stands at its left side; the arch is fenced off and closed to entry.

The rock arch was shaped over centuries by the erosion of coral limestone through ocean currents and wave action. The arch changes slowly over time, and small sections have broken away in past decades.

The name Sunayama refers to the sand hill that visitors cross before the beach comes into view. The beach is not an officially designated swimming area and has no lifeguards or lifesavers; in summer, operators rent leisure equipment, and since April 2019 only licensed businesses meeting conditions such as lifeguard staffing may operate in marked zones.

The rock arch has been fenced off since October 2018 because of falling rocks, so it cannot be approached. Free parking, changing rooms, showers and toilets stand on the landward side of the sand hill, a short walk from the water. There is no official swimming beach, no lifeguards, and two fatal drownings occurred in 2014 during wave advisories.

The rock arch has long shed stones, so a wire mesh was once fixed over its upper side; after the mesh deteriorated, a protective fence was put up in early October 2018 and the area around the arch is closed to entry, with the closure expected to continue for the time being.