Tomogashima (Wakayama), 3rd Battery Ruins on Okinoshima Island


Discovery of Abandoned Military Ruins

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Tomogashima is a group of 4 uninhabited islands located at the southern entrance of the Osaka Bay in the Kitan Strait, between Wakayama and Awaji-shima in Japan. Boats connect Kada Port to the main island called Okinoshima and home to several 19th and 20th century military ruins, a lighthouse and a few camping sites opened in summer.

Tomogashima archipelago belongs to the Setonaikai National Park, and encompasses Jinoshima, Kamijima, Okinoshima and Torajima islands. These 4 islands, which were a former military defense zone, are now uninhabited and deserted. They make an ideal destination for urbex in Japan, and without much risk as exploration is allowed.

Located in the north of Wakayama City, and about 1h30 by train 🚅 from Namba in the south of Osaka, Kada Port harbors the only boat serving Okinoshima, Tomogashima's main island. Passengers disembark at Nonaura Port, and with a simple map in Japanese, go exploring what remains of the Japanese Imperial Army’s presence from the Meiji Era (1868 - 1912) to the World War II.

Tomogashima (Wakayama), 3rd Battery Ruins on Okinoshima Island 2

Vegetation-covered battery guns

Five artillery batteries, built of red bricks and still displaying period canons, are to be discovered in Okinoshima. They were all settled on the same side of the island: in the west, that is to say on the right-hand side when disembarking from the ferry ⛴️. These military units were protecting the Kitan Strait, the entrance to Osaka Bay, from pirate ships and various enemy warships.

The third battery ruin is the largest. One can enter inside and go through the underground tunnels light by few lights laid on the floor, then end up in bunker type shelters and a small circular courtyard. The feeling of loneliness is strong, and the slightest noise is amplified by the hermetic fortifications. If you are afraid of the dark, make sure to bring an additional flashlight. Not all the buildings are preserved enough to allow visitors, and for those that are falling in derelict, especially the second battery, one can only watch the slowly crumbling facades.

Due to the lush vegetation claiming its rights back on the human battlements, some landscapes of the island remind of Hayao Miyazaki’s movie Castle 🏯 in the Sky. Nicknamed "Laputa Island", Okinoshima is by the way frequently used as a shooting set for movies or television series.

Tomogashima (Wakayama), Panorama from Mount Takanosu's Observatory on Okinoshima Island

Forest trails and panoramic views

Tomogashima offers a range of forest hikes thanks to the greenery spreading over most of the deserted islands. On Okinoshima, the walking trails network was designed to bring visitors to the main points of interest of the island, that is to say:

  • The ruins of the Japanese army’s 5 abandoned batteries;
  • Tomogashima’s white lighthouse and its western architecture;
  • Jagaike Pond, and,
  • Mount Takanosu Observatory, the highest point of the island.

The trail is easy for hiking amateurs, with signs at each intersection and a gentle steep gradient. It is recommended to wear suitable walking shoes and to bring a picnic and enough water, especially when the weather is very hot.

The elevated views on the rocky seaside, the blue of the sea and the green of the treetops are very pleasant and help getting over the trashes stranded by the sea. As for the wildlife, you will encounter many snakes during summer, squirrels, a few deer and peacocks that were introduced on the island specially to limit the snake population.

Note that the eastern part of Okinoshima island is the wildest and sometimes off limit for security reasons, after a typhoon 🌀 for example. On thie eastern end, a path appears between the rocks at low tide to reach Torashima, and its own Battery Ruins.

Around Nonaura port, you will find amenities such as toilets 🚽, a visitor center, a small cafe and lawns that are used as camping sites. In summer, it is not unusual to meet Japanese families with tents and luggage arriving on the island for the weekend. Swimming areas in the sea are also available but they don’t have much interest.

The excursion to Tomogashima can be envisaged as a one-day trip from Osaka, to complete with the visit of Kada port, renowned for its onsen ♨️ hot springs and Awashima-jinja shrine famous for its Hina Matsuri 🎎 festival dolls collection.

⬇️ Further down this page, discover our visit guide in Tomogashima and around.
By Kanpai Updated on April 28, 2023 Tomogashima