Shetland Islands Council has voted to study whether it can build undersea tunnels to connect its scattered islands. This moves a plan that has been discussed for years into a real testing phase.

The council also plans to map out how to pay for the project over 30 years. According to the Financial Times, the council will develop a detailed financing plan.

The project would involve four tunnels. One would connect the Shetland mainland to Yell. Another would link Yell to Unst, the northernmost inhabited island in Britain. A third would go to Whalsay, and a fourth to Bressay. Sky News puts the total cost at around £1.5 billion — making this one of the largest infrastructure projects ever planned by a local council in the UK.

Each tunnel serves a practical purpose. Right now, people travel between islands by ferry. The ferries take time and cost money. Ferry schedules affect almost everything on the islands: when children can attend school, how fishing businesses operate, how quickly goods move. Tunnels would remove these constraints. People and goods could move freely, just as they do on mainland Britain.

Building tunnels under the sea is not a new idea. The Faroe Islands completed a similar project over 20 years. Norway built comparable tunnels in the 1990s and beyond. But those projects had a key difference: national governments paid for them. Shetland is governed by a local council, not a national one. The council will need to persuade the Scottish Government and possibly the UK Treasury to help fund such an expensive project.

The council published a planning update in September 2023 that identified these four tunnels as the preferred option. The council voted in June 2025 to commission the detailed feasibility study. The time between those two steps was spent building a strong enough case to justify spending money on construction planning.

The 30-year financing plan is worth understanding, because it shapes how the council will ask for money. Rather than asking for a single lump sum, spreading costs over three decades aligns better with existing UK funding programmes — like the Levelling Up fund and the UK Infrastructure Bank. It also allows planners to test different payment models: private companies might finance it in exchange for toll revenue, or bonds could be issued backed by the money saved from not running ferries. The feasibility study will need to work out whether any of these options actually work.

Geography makes this challenging. Shetland lies about 170 kilometres north of mainland Scotland. The seabed, tides, and weather are different from, say, a Norwegian fjord — where tunnelling companies have experience and equipment already in place. Building tunnels in remote, cold, maritime conditions carries extra costs and risks that must be measured before any financing plan makes sense.

The context here is simple: about 23,000 people live on Shetland's islands. Ferry dependency is the single biggest limit on their economic opportunity. Someone in Shetland cannot easily drive to a job on another island, attend university on the mainland, or schedule a medical appointment without coordinating around ferry times. Removing that constraint would change daily life. But whether building £1.5 billion worth of tunnels is the right answer — and who will actually pay for it — is what the study must determine. The council is asking the question seriously now. The hard part comes next.