Sociedade União 1º Dezembro of São Pedro de Sintra dates back to 1 December 1880, when it was founded as a philharmonic and recreational society; a sports section followed in the 1930s and the football section was formally created on 6 April 1938. The club plays at the Campo Conde Sucena.

Its women's team was the dominant force in Portugal for over a decade, winning twelve national championships and seven cups.