A recent study has confirmed that the underwater tunnel project linking Morocco and Spain is technically feasible, with the first phase expected to take between six and nine years and total costs estimated at around €8.5 billion. DR ‹ › A study conducted by German engineering firm Herrenknecht, a global leader in tunnel boring machines, and commissioned by Spain's Secegsa as part of studies on a fixed link across the Strait of Gibraltar, has confirmed that an underwater tunnel connecting Morocco and Spain is technically feasible. The study concludes that a tunnel linking the two countries can be built using existing technology and engineering capabilities. It estimates that the first phase of the project would take between six and nine years, with key milestones expected to be reached between 2035 and 2040. Despite this positive assessment, the report stresses that the project would rank among the largest and most complex engineering undertakings in the world, both in scale and in terms of technical and geological challenges. The total cost is estimated at around €8.5 billion, covering the drilling of an exploratory tunnel, construction of the main tunnels, terminal stations, and the full range of technical, operational, and safety equipment. The findings are particularly significant as they provide a technical basis for evaluating the project's feasibility in the highly sensitive Camariñal Threshold, a section of the strait known for its complex geological conditions. This area represents one of the main engineering challenges that must be overcome to ensure the tunnel's safety and long-term durability. Tunnel design and technical challenges The proposed route adopts a rail-only design, definitively excluding any mixed road use. The project consists of two parallel underwater tunnels, each carrying a single railway track in opposite directions, along with a separate service and safety tunnel. The tunnel would reach a maximum depth of around 475 meters below sea level, deeper than the Channel Tunnel, making it one of the most challenging underwater tunnelling projects ever undertaken. At such depths, drilling would be carried out under pressures of approximately 50 bars, while also addressing soil expansion phenomena. The study concludes that these conditions remain within the limits of current technology, provided that tunnel boring machines are specifically engineered for this environment. Compared to plans proposed 15 years ago, the final design increases the tunnel diameter from 8 to 8.8 meters, with tunnel lining thickness varying by section to improve railway operating conditions. On the Spanish side, the northern terminal has been relocated to the vicinity of Vejer de la Frontera, improving connectivity with high-capacity rail lines and major highways. The tunnel section within Spanish territory would extend 39.1 kilometers, with the crossing time between the two continents estimated at around 30 minutes. Renewed political momentum The project regained momentum between 2022 and 2023, amid a new phase in Moroccan-Spanish relations following Spain's shift in position on the Western Sahara issue. In this context, both countries agreed to officially relaunch the project after years of stagnation, reopening discussions around one of the most ambitious infrastructure proposals linking Europe and Africa.
