Daily commute from Fort Kochi to Ernakulam, especially places like High Court Junction, will save a passenger ₹1500 per month and reduce travel time by 2 hrs, with the implementation of the proposed underwater tunnel project connecting Fort Kochi and Vypin, according to the Feasibility report of the project. The twin tube tunnel is expected to provide major relief to thousands of residents and commuters who now endure a 16 km detour through the Goshree bridges or long waits for the Fort Kochi–Vypin ferry. 

According to the report, an average traveller takes about two and a half hours to go from Fort Cochin to the High Court junction in Ernakulam and back, and he has to spend about ₹300 as auto fare. “Through the channel tunnel, he will spend just ₹50 or ₹100 and half an hour for the journey. A daily commuter in a month can save a minimum of ₹1500 per month and his valuable 60 hours. Similar savings will accrue to trucks and other traffic using the tunnel,” the report said.

Kerala’s first underwater tunnel, a direct link between the two shores separated by the busy Cochin Port shipping channel, has moved a step closer to reality, with the state government directing the Kerala Rail Development Corporation Limited (KRDCL) to invite Expressions of Interest (EOI).

The project seeks to bridge a crucial “missing link” in the upcoming Kerala Coastal Highway, which is interrupted by the Cochin Port’s shipping channel between Fort Kochi and Vypin. At present, commuters either rely on ferries or take the "torturous and circuitous” Goshree route, which is a 16 km drive that could soon shrink to just 2.5 to 3 km if the tunnel materialises, as per the KRDCL report seen by Onmanorama.

An overbridge option was considered, but the report firmly rejected it as “technically difficult and financially not viable.” A bridge would have required a 50-60 metre clearance for ships and a 500-metre clear span, making it both costly and unsafe for navigation. The report notes that the seabed soil is also unlikely to support the massive foundations required as a reason to avoid a bridge, noting that a tunnel offers uninterrupted passage for ships and safer road connectivity.

KRDCL Managing Director V Ajith Kumar said that they have conducted a study and submitted it to the government. “Since it is a shipping channel, constructing a bridge is not practical. It will have to be constructed at such a height to permit the ship traffic. Moreover, the land acquisition process will also be strenuous. If we construct a tunnel, we will have to acquire only 100m of land on both sides of the landing points. So a tunnel is the most viable option here,” he said.

Twin-tube tunnel design 
The proposed structure will consist of two parallel tunnels, each carrying a highway lane and a service lane. With an external diameter of 12.5 m and an internal width of 11.25 m, the tunnels will run 35 m below sea level, providing 20 m of water depth for ships, accommodating future port development, and a 15-metre soil cushion for tunnelling stability.

The total length is 2.75 km, including 1.75 km of bored tunnel and 1 km of cut-and-cover approach sections at both ends. The design includes emergency stop bays every 250 m and escape routes every 500 m with ventilation, ensuring global safety standards.

According to the report, Kochi’s variable soil structure poses the project’s biggest challenge. The primary construction method recommended is a Tunnel Boring Machine (TBM). The report notes that while "stiff marine clay" exists at the deeper levels, the upper soil levels consist of "loose nature of the alluvial deposits" and have "high porosity with loose water bearing". This will necessitate a specialised "Slurry Face TBM", similar to that used in the ongoing Mumbai Coastal Road Project.

The report also cites land acquisition as another obstacle. The shortest alignment requires 2.79 hectares, affecting around 285 buildings and structures, including 125 in Fort Kochi and 160 in Vypin. The Fort Kochi side poses more difficulty due to high land value and dense development.

The total estimated project cost is ₹2,672.25 cr, with the bored twin-tube tunnels accounting for ₹1,225 cr and land acquisition ₹500 cr. Construction is projected to take 30 months, plus 18 months for land acquisition, targeting completion by September 2027 if work had begun by April 2025.

K-Rail’s analysis pegs the Economic Internal Rate of Return (EIRR) at 9.52 per cent, terming the project economically sound and feasible.

​This viability is supported by strong traffic projections. In 2022, the existing ferry services carried 5,531 vehicles per day. The tunnel is projected to handle 9,325 PCU (Passenger Car Units) per day in its opening year (2025), even with a toll, a figure expected to rise to 17,119 PCU per day by 2040.

The Kerala Infrastructure Investment Fund Board (KIIFB), which funds the coastal highway project, is expected to fund the tunnel project too.

The report also recommends developing a Detailed Project Report (DPR). This DPR must include several ‘Essential Studies’ ​like a detailed traffic study, topographical and Alignment studies using Drone or other methods, environmental impact assessment (EIA) and social impact assessment (SIA) ​Hydrological/oceanic studies, and geological and geotechnical surveys of the channel bed and approach areas. 

With toll potential, the feasibility study recommends implementation under a Public-Private Partnership (PPP) — through Design-Build-Finance-Operate-Transfer (DBFOT) or Build-Operate-Transfer (BOT) models. The main tunnel will be at a depth of 35 m from sea level (low sea level), depending on the type, size and design of the tunnel bores, giving around 20m draught for the shipping path and 15 m soil cushion above the tunnel required for TBM tunnelling, the report notes.