West Area

The placid Kanmon Straits separate Honshu’s southwestern tip and the northernmost peninsula of Kyushu. Ferries and sightseeing boats leave from both sides. Every August, the huge Kanmon Straits Fireworks Festival lights up the night sky.

Heading southeast along Kyushu’s coastline, you’ll find the Kunisaki Peninsula and Mount Futago. This mountain’s slopes are dotted with temples and shrines, many associated with Rokugo Manzan, the peninsula’s blend of Shintoism, Buddhism and mountain worship. Nearby is Daifudo Cave, an ancient training ground for monks on the Kunisaki Peninsula Long Trail.

Near Mount Futago is Hime Island, a rugged isle with scenic views, particularly from Cape Kannon. Hime Island offers relaxing hot springs and interesting geology. Cycling is the ideal way to explore here.

To the north is Yashiro, where Japan’s largest colony of Alveopora japonica, a delicate coral, lies offshore. You’ll need to go diving to see it. Yashiro is also a departure point for eco-tours to spot playful finless porpoises.

Farther up Hiroshima Bay is Miyajima, home to the huge red torii of Itsukushima-jinja Shrine, a UNESCO World Heritage site. Southwest of the shrine is the Ramsar Wetland, habitat for the delicate blue Miyajima dragonfly (Orthetrum poecilops miyajimanense), and Mount Misen, with sweeping views from its ropeway and observatory as well as several excellent trekking courses. 

One fun option is the Shimanami Kaido cycling course, which spans six islands and covers 70 kilometers, connecting Onomichi on Honshu and Imabari on Shikoku. You can rent bikes and drop them off at several points along the way. On Hakata Island, you can take sightseeing boats to see the Funaori Seto Strait’s whirlpools up close, and Oshima Island has the fascinating Murakami Suigun Museum, all about the region’s Murakami pirates. 

East Area

Tomonoura on Honshu is the area’s archetypal historic port town. Walking around its narrow streets with ancient temples and shrines, low-roofed buildings, and harbor-side warehouses feels like stepping back in time. Offshore is the sparsely inhabited Sensuijima Island, where you can swim off golden beaches, hike the whole island, and marvel at Goshikiiwa’s multi-hued volcanic rocks.

Farther east near the canal city of Kurashiki is Mount Washu. The peak’s main draws are outdoor activities and views of the island-studded Bisan-Seto Strait. At Mount Washu’s foot is Shimotsui, a historic fishing town. Some coastal mudflats here are home to the Japanese horseshoe crab.

The coast of northeastern Shikoku is connected to Shimotsui by the world’s longest two-tiered bridge, Seto Ohashi Bridge. Negoroji, a Buddhist temple near the five peaks of the Goshikidai Highland, is a stop on the 88-temple pilgrimage around the island.

Three islands between Shikoku and Honshu—Naoshima, Teshima and Inujima—have become known as contemporary art outposts since a corporate project brought art to Naoshima in the 1980s. It revitalized the island and enriched the lives of residents, and did the same on Teshima and Inujima. Today, these “art islands” offer museums and installation pieces, a laid-back atmosphere, and quiet roads for walking or cycling. Around a million visitors attend the Setouchi Triennale international art festival, held every three years on many Seto Inland Sea islands.

To the east, Shodo Island has a near-Mediterranean climate, making it the natural choice for Japan’s first olive plantation. This island is an excellent departure point for trips to see finless porpoises.

Off the island of Awaji Island is the Naruto Strait, a narrow channel where rapid currents generate powerful whirlpools, best viewed up close on a sightseeing boat. Keino-Matsubara on the island’s western coast has a pine-backed beach good for camping.

East of Awaji Island is a 3-kilometer sandbar called Naruga Island, whose salt marshes are a great place to spot rare plants and animals. Across the Kitan Strait from Naruga Island is the Tomoga Island group, full of fascinating military ruins and great for hikes through wooded slopes.

North of Awaji Island is the Akashi Strait, spanned by the elegant Akashi Kaikyo suspension bridge. The Rokko mountain range looms over the city of Kobe, where the bridge ends. Its tallest peak, Mount Rokko (931 m), provides a good viewpoint for panoramas of the sea and the cities of Kobe and Osaka. 

Culture

Life in the Seto Inland Sea area has always been about the sea. The region was long known for fishing, and, from the Edo period onward, for the Seto Inland Sea Route. This trade route ran from what are now Hokkaido and Okinawa and on to Korea and China, stopping at historic port towns such as Ushimado in Okayama Prefecture, Onomichi in Hiroshima Prefecture and Murozumi in Yamaguchi Prefecture.

Seto Inland Sea's noteworthy festivals include Tomonoura’s Bentenjima Fireworks Festival and Itsukushima’s Kangensai, which features mikoshi (portable shrines), decorated wooden boats and gagaku (traditional Japanese court music).

Contemporary art is part of Seto Inland Sea culture. Since the 1980s it has been a hub for art events. Around a million visitors now attend the Setouchi Triennale international art festival. The festival was introduced in 2010 and is held every three years across many Inland Sea islands.