Tokyo Port Tunnel

Two parallel road tunnels beneath Tokyo Port connect Oi in Shinagawa with Odaiba in Koto City. The Shuto Expressway tunnel (opened 1976, immersed-tube method) and the toll-free National Route 357 tunnel (westbound 2016, eastbound 2019, shield method) together form the bay's principal road crossing.

Two Tubes Beneath the Harbour Floor

Between Yashio in Shinagawa and Aomi in Koto City — the twin waterfronts of Tokyo Port — two road tunnels run side by side through the seabed. The first is the Shuto Expressway Bayshore Route’s Tokyo Port Tunnel: an immersed-tube structure approximately 2.8 kilometres long that opened in August 1976 as the seed of what would become the 62.1-kilometre Bayshore Route. The second is a toll-free general-road tunnel on National Route 357 (Tokyo Bay Coastal Road), about 1.9 kilometres long, built as a parallel relief route to the expressway.

The Route 357 tunnel opened in two stages. The westbound bore toward Kanagawa opened on 26 March 2016; the eastbound bore toward Chiba followed on 3 June 2019, completing the crossing. The eastbound tunnel was excavated by a shield boring machine with an outer diameter of 12.2 metres. With both bores open, National Route 357 became a continuous, toll-free coastal road linking the Haneda Airport area with Chiba — a journey previously requiring either a toll expressway or a long diversion.

Port Logistics and the Bay’s Road Network

The significance of the Tokyo Port Tunnel lies in its relationship to the port’s freight economy. Oi Wharf, sitting directly above the western approach, is one of Japan’s largest container terminals and operates around the clock. The Shuto Expressway tunnel carries heavy freight vehicles on the paid express route into the bay-area network; the parallel Route 357 tunnel handles general traffic on the free alternative. Together, the two bores reduce the pressure on Oi Wharf’s surrounding roads and provide the port district with redundancy in its access corridors.

Since the 2019 completion of the eastbound bore, travel between Haneda Airport and the Odaiba district via general road became notably quicker, reportedly transforming traffic patterns across the bayside. The pairing of a 1976 immersed-tube expressway and a 2019 shield-bored general road reflects how Tokyo’s port infrastructure was built in layers — each decade adding capacity onto the previous.

Summary

The Tokyo Port Tunnel is a doubled crossing beneath the harbour: the Shuto Expressway bore from 1976 and the parallel Route 357 bore completed in 2019 together carry paid and free traffic across the same stretch of seabed. They are a tangible reminder that Tokyo remains, fundamentally, a port city built outward onto reclaimed water.

Drive Route 357 westbound through the tunnel and you surface at Oi with the container cranes of Tokyo Port stretching to the horizon. It pairs well with a drive along the Bayshore Route or a visit to Tokyo Portcity Takeshiba for a wider sense of how the waterfront has been layered over the decades.

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