In the early twentieth century a few architects such as Valentín Casalís (Pinares Palace, Santander) and Joaquín González Riancho (house of Don Adolfo Pardo, Santander) joined the search for a Spanish national architecture. In the 1920's Leonardo Rucabado popularised regionalist montañés ("highland") architecture, defined by an historicistic expression of montañés architecture of the 16th, 17th and 18th centuries. Rucabado carried out significant works in Santander, like the Menéndez Pelayo Library and Museum, and the La Casuca and El Solaruco buildings. This trend was later followed by various national and regional architects (Central Post Office of Santander, by Secundino Zuazo and Eugenio Fernández Quintanilla).

From 1925 onwards the classical and regionalist tradition began to be rejected, and what came into favour in its stead was a whole amalgam of international influences deriving both from a rationalistic conception of architecture ( Rationalism, Constructivism,, neo-Positivism) and from more Utopian currents (Futurism and Expressionism). The best architecture carried out in Cantabria during this period arose from a conjunction of both trends, as can be seen in the works built in Santander by José Enrique Marrero (Siboney building), Gonzalo Bringas (Club Marítimo) and Eugenio Fernández Quintanilla (Maria Lisarda theatre, presently the Coliseum cinema).

After the Spanish Civil War (1936-39) architecture became impregnated with a certain traditionalism that encouraged a preference for Spanish materials, techniques and themes. The grandiloquent town-planning of Isabel II and Lealtad streets, and attempts at the monumental (Central Stations, Plaza Porticada) that were undertaken in the reconstruction of Santander after the 1941 fire, express this trend. A few architects, however, like Luis Moya, eschewed traditionalism and sought more modern solutions for their works (church of Virgen Grande in Torrelavega). Very gradually there occurred an architectural renovation of form: now through the influence of an "international style" (Olano House, La Rabia, Comillas); now by means of organicist solutions, or by the creation of new spatiality, using new materials like concrete and glass.

From the 1960's Cantabrian architecture became integrated within the international scene, characterised to the present day by a total diversity. Some recent constructions, like the Palacio de Festivales in Santander manifest a vindication of a postmodernist architecture. Conversely, other architects prefer to revisit the ideas of the Modernist Movement (Casa de la Lluvia in Liérganes).