It took the Nieuports into World War I, but was then re-equipped with Morane-Saulnier L monoplanes on 28 February 1915.

By this time, the unit was assigned to V Armee of the French ground forces.

On 16 May 1918, Escadrille Spa 12 was cited by General Philippe Pétain for its prowess in destroying 34 enemy aircraft and two observation balloons.

When the war ended five days later, Escadrille Spa12 had been credited with victories over 43 enemy aircraft and seven observation balloons.

[1] The heritage of the Escadrille 12 continues in the present day French air force.