Cobalt Blue Beach, Tsunoshima

Cobalt Blue Beach sits on Tsunoshima Island, reached by driving across the striking 1,780-meter Tsunoshima Bridge from the Hohoku coast north of Shimonoseki. The beach takes its name from the strikingly clear, pale-turquoise water that forms over its white sand seafloor on sunny days, a color effect close enough to tropical water that it has become one of the most photographed beaches in the prefecture, often paired with shots of the bridge itself on the approach. Swimming and snorkeling are the main draws in season (roughly June-September), when shower facilities operate and the nearby Shiokaze no Sato rest area provides food stalls and restrooms for a full beach day.

Because the beach sits on an island with no direct bus service, a rental car is by far the easiest way to visit, crossing the toll-free bridge in a few minutes from the mainland; the drive is about 45 minutes from central Shimonoseki or roughly 1 hr 45 min from Yamaguchi City. The bridge crossing itself, with the road running low and close to the water, is often as much a highlight as the beach for first-time visitors, and the roadside parking area partway along makes a natural stop for photographs before continuing on to the sand.

Beyond swimming, the island continues to Tsunoshima Lighthouse at its far end, a still-operating Meiji-era stone lighthouse with coastal walking paths and dramatic sea-cliff views, and to seafood restaurants known locally for fresh sea urchin (uni) in season. Because the beach's signature turquoise color depends heavily on sunlight, a clear, sunny day between late spring and early autumn gives the most striking visit, while the bridge drive remains scenic in any weather.