Ōnaruto Bridge

A 1,629-metre suspension bridge opened in June 1985 spanning the Naruto Strait between Awaji Island and Naruto, Tokushima. The bridge deck houses a 450-metre enclosed walkway — the Uzunomichi — with glass floor panels looking straight down at the famous Naruto whirlpools 45 metres below.

Use

Bridge

Area

Naruto City / Minamiawaji City

Completed

1985

Height

125.93 m

Developer

Honshu-Shikoku Bridge Expressway Company (formerly Honshu-Shikoku Bridge Authority)

Crossing Above the World’s Great Whirlpools

The Naruto Strait, between the southern tip of Awaji Island and Naruto City on Shikoku, is one of the fastest tidal channels anywhere in Japan. At spring tide, currents can exceed ten knots and whirlpools up to twenty metres in diameter form as water rushes between the Pacific Ocean and the Seto Inland Sea. It was across this turbulent channel that the Ōnaruto Bridge opened on 8 June 1985.

The bridge carries the Kobe-Awaji-Naruto Expressway (E28) on its upper deck, spanning 1,629 metres in total with a main span of 876.3 metres. Its towers stand roughly 125.93 metres above sea level. The structure was engineered as a stiffened truss suspension bridge, designed to resist the extraordinary hydraulic forces generated by the tidal race below. Construction was managed by the Honshu-Shikoku Bridge Authority, the same public body responsible for the Akashi Kaikyo Bridge to the north.

A Walkway Through the Bridge — and Over the Whirlpools

What makes the Ōnaruto Bridge unlike almost any other bridge in the world is what lies inside its lower deck. Designed from the outset with space for a future Shinkansen rail line, the unused lower truss has instead been partially converted into the Uzunomichi (渦の道, Whirlpool Way): a 450-metre enclosed pedestrian walkway suspended 45 metres above the strait. At regular intervals, glass floor panels cut into the walkway offer a direct view straight down to the swirling water below — a perspective unavailable from any ship or shore.

The Naruto whirlpools are listed among the world’s three great tidal currents, alongside the Saltstraumen in Norway and the Old Sow in Canada. For tourists arriving from Osaka or Kobe, the bridge and the Uzunomichi form the natural entry point to Shikoku, combining infrastructure spectacle with a natural phenomenon in a single visit. The bridge predates the full opening of the Kobe-Awaji-Naruto Expressway by over a decade, having opened in 1985 while the Akashi Kaikyo Bridge would not be completed until 1998.

Summary

The Ōnaruto Bridge, opened in June 1985, spans 1,629 metres across the Naruto Strait on 125.93-metre towers, connecting Awaji Island to Naruto, Tokushima. Its lower deck conceals the Uzunomichi walkway where glass-floor panels give visitors a direct view of the famous tidal whirlpools below. Few crossings in Japan combine engineering ambition and natural spectacle as seamlessly — allow extra time to walk the bridge from the inside.