San FermÃ n ( or Sanfermines ) is an annual festival held in the city of Pamplona ( Navarre , Spain ) . It starts at 12:00 on 6 July with the setting off of a rocket . The festival of San FermÃ n ( or Sanfermines , in basque language Sanferminak ) in the city of Pamplona ( Navarre , Spain ) , is a deeply rooted celebration held annually from 12:00 , 6 July , when the opening of the fiesta is marked by setting off the pyrotechnic chupinazo , to midnight 14 July , with the singing of the Pobre de MÃ .