Construction of the Somport railway tunnel was inaugurated on the French side on 12 July 1912, and after delays in its construction due to World War I, completed in 1915.
Spanish project engineer Ramírez de Dampierre began construction of the station in 1923, and it was formally opened on 18 July 1928, in the presence of King Alfonso XIII of Spain and the president of the French Republic Gaston Doumergue. The large size of the station and infrastructure was necessitated in part by the need to transfer all transiting passengers, baggage and freight between Spanish and French trains, because the French rail standard gauge of 1,435 millimetres (4 ft 8.5 in) was incompatible with the Spanish gauge of 1,672 millimetres (5 ft 5.8 in) at the time and hence prevented through-traffic. This transformed a simple customs-control exercise into a lengthy logistics exercise. The site includes a large locomotive depot, two sheds for the transshipment of freight between French and Spanish trains, various other outbuildings and a resultant extensive layout of tracks.
Due to the Franco-Spanish international convention under which it was built, the Somport railway tunnel and quasi-French control of the French-side of Canfranc international railway station continued during World War II. The Spanish authorities came to an operational agreement with the Nazi German Wehrmacht authorities, where by passenger train services continued, with freight-trains carrying mined tungsten north, and French grain plus trans-shipped Swiss gold south.
The station's raison d'être came to an abrupt halt in 1970 when a train derailment demolished a bridge on the French side of the mountains. Under financial pressure from French national railway company SNCF, the French government decided not to rebuild the bridge, and hence the cross-border line was closed.