Taihu Tunnel Opens: What a 10.79 km Underwater Highway Means for Freight

Last updated: October 6, 2026

After nearly four years of construction, China has officially opened the Taihu tunnel, a 10.79-kilometer underwater highway running beneath Lake Taihu in Jiangsu Province, roughly 50 kilometers east of Shanghai. Drivers began using it when the broader Changzhou-Wuxi Highway opened on December 30, 2021.

For anyone watching the freight industry, the opening is more than a ribbon-cutting. It reshapes a key corridor in the Yangtze River Delta, the manufacturing belt that keeps a lot of global supply chains moving. Below is the quick rundown, then what it actually changes for carriers.

What happened

• The tunnel stretches 10.79 km (6.65 miles) under Lake Taihu in eastern China's Jiangsu Province.
• Construction began January 9, 2018, and lasted nearly four years, with public access beginning December 30, 2021.
• Officials in Jiangsu reported a cost of about 9.9 billion yuan (roughly $1.56 billion).
• The two-way tunnel has six lanes, is 17.45 meters wide, and used over 2 million cubic meters of concrete.
• It links expressways serving Suzhou, Wuxi, and Changzhou, offering a new route between Shanghai and Nanjing.
• The ceiling features colorful LED lighting designed to prevent driver fatigue.

How the new corridor fits the Yangtze River Delta

The Yangtze River Delta is one of the densest freight-generating regions on Earth. Suzhou, Wuxi, and Changzhou host clusters of electronics, automotive parts, textiles, and chemicals shippers. Before this tunnel, trucks running between Shanghai and Nanjing had to skirt the southern shore of Lake Taihu on older surface roads.

The new highway gives those trucks a dedicated expressway bypass, with the lake-spanning tunnel at its core. That means fewer signalized intersections and less interaction with commuter traffic. For a dispatch planner, consistent transit time is among the most valuable variables when pricing a lane for shippers.

Why it matters

Why does a Chinese highway tunnel matter to readers outside China? Because supply chains are interconnected. The Yangtze River Delta feeds a significant share of global containerized goods moving through Pacific ports. Faster, more reliable road transport between manufacturing hubs and port cities can compress order-to-delivery windows, tighten inventory cycles, and shift the competitive position of certain routings.

Among comparable underwater highway tunnels worldwide, Taihu ranks second only to Norway's 14.3-kilometer Ryfast tunnel, but it surpasses Japan's 9.6-kilometer Tokyo Bay Aqua-Line submerged section. The scale of investment—roughly $1.56 billion—signals continued infrastructure prioritization around China's coastal manufacturing regions.

The tunnel's immediate practical benefit is structural: it connects expressways that previously required surface-level transitions, creating a more smooth corridor. Whether that translates into freight industry wins depends partly on what happens next.

What to watch

First, monitor for tunnel-specific restrictions. Long underwater road tunnels frequently carry hazmat prohibitions, height limits, or weight constraints that affect which freight can use the route. Until those parameters are confirmed, routing sensitive loads through Taihu carries unknown risk.

Second, watch whether connecting feeder roads around Suzhou and Changzhou receive upgrades in parallel. The tunnel becomes a true freight corridor only if the roads feeding into it keep pace. If feeder improvements lag, the tunnel functions as a fast segment inside a slower network, limiting its practical impact.

Third, observe carrier behavior over the first six months. If major 3PLs and asset-based carriers shift volume to the new expressway, spot rates on the older surface route between Suzhou and Wuxi will soften. If they don't, it signals that the feeder-road bottleneck matters more than the tunnel itself.

A worked scenario for a dispatcher

Consider a 3PL moving auto-parts from a Suzhou supplier to a Nanjing assembly plant. Before the tunnel, that run involved surface roads around southern Lake Taihu, where urban congestion introduces variability into delivery windows.

Routing the same load over the new expressway and Taihu tunnel could reduce that variability. Fewer traffic signals and less urban driving mean fewer variables for the dispatcher to absorb. The customer's delivery window becomes more defensible. The lane becomes easier to quote without building in excess buffer time.

Whether that translates to better margins, competitive quotes, or both depends on how quickly the industry reprices the lane.

Key takeaways

• At 10.79 km, the Taihu tunnel is China's longest underwater highway tunnel and outpaces the Tokyo Bay Aqua-Line's 9.6 km submerged section.
• By connecting Suzhou, Wuxi, and Changzhou expressways, the tunnel creates a more smooth corridor between Shanghai and Nanjing.
• Primary near-term benefits are reduced congestion and fewer traffic signals compared to surface alternatives.
• Watch for tunnel-specific hazmat, height, and weight restrictions before routing sensitive freight.
• Feeder road improvements will determine whether this becomes a structural freight corridor or a fast segment inside a slower network.