The Coen Tunnel (1966) is a tunnel in the A10 motorway under the North Sea Canal in western Amsterdam. The tunnel is named after the Coen port in the vicinity which was named after Jan Pieterszoon Coen. The tunnel itself is 1283 metres long of which 587 metres are fully covered. The tunnel connects the Zaan district with the western part of Amsterdam. The tunnel reaches a maximum depth of 22 metres.
Before the tunnel was built the Hem ferry and, to a lesser degree, the Schellingwouder bridge was the most important connection between Amsterdam and Zaandam which formed a serious bottleneck for traffic. In 1959 5.800 vehicles were ferried daily and waiting times reached 45 minutes or more. In the 1950s inhabitants petitioned successfully for a tunnel under the North Sea Canal.
Construction commenced in 1961 and the total cost amounted to 45 million Dutch guilders. The opening of the tunnel was inaugurated on the 21st of June 1966 by Queen Juliana.
Since its opening the tunnel has been a great success. Currently with more than 100.000 vehicles passing daily congestion is once more an issue. A second Coen Tunnel has been procured under a Public-private partnership structure and construction started in the summer of 2009. May 13, 2013 the new tubes opened for traffic and the old tubes were closed for extensive renovation. It is expected that all four tubes will be available for traffic mid 2014.