A feasibility study by Herrenknecht confirms that a 38.5 km twin-tube railway tunnel between Spain and Morocco under the Strait of Gibraltar is technically feasible using current construction methods. The tunnel is to run at a depth of 175 to 475 m below sea level, of which 28 km will be under the sea. The construction of the Spanish section is estimated to cost around EUR 8.5 billion, with the logistical and financial requirements considered to be high. Spain is planning to publish a tender for an exploratory tunnel lasting up to nine years from 2027. Alternatives to the Algeciras – Tangier line and additional uses for data and power cables are also being examined.
