The F.K.58 was originally ordered to serve with AdA units based in French overseas territories.
Following the outbreak of war with Germany, however, the type was assigned to an ad hoc, Free Polish air force unit commanded by Captain Walerian Jasionowski.
Roughly equivalent to a French escadrille, or Polish eskadra, it was often known by the unofficial name "Eskadra Koolhoven".
The unit's official role was patrouille ("patrol") – as the AdA designated units that defended rear areas against long-range bombers and other enemy aircraft, as part of the Défense Aérienne du Territoire ("Territorial Air Defense"; DAT).
The unit operated from the Salon and Clermont-Aulnat air bases.

By May 1940, 13 aircraft were operational with Eskadra Koolhoven.
 As delivered, however, the fighters were unarmed and the Poles had to acquire machine guns and fit them.
From 30 May 1940, they were in service, patrolling firstly in the Avignon-Marseille area, and then over Clermont-Ferrand.
At least 47 operational sorties were recorded, but the Escadron did not encounter enemy aircraft.

The type's service life was short-lived, with ; the unit had no confirmed victories, but at least one F.K.58 was lost.
After the fall of France, all surviving airframes were scrapped.
The F.K.58 was originally ordered to serve with AdA units based in French overseas territories. Following the outbreak of war with Germany, however, the type was assigned to an ad hoc, Free Polish air force unit commanded by Captain Walerian Jasionowski. Roughly equivalent to a French escadrille, or Polish eskadra, it was often known by the unofficial name "Eskadra Koolhoven". The unit's official role was patrouille ("patrol") – as the AdA designated units that defended rear areas against long-range bombers and other enemy aircraft, as part of the Défense Aérienne du Territoire ("Territorial Air Defense"; DAT). The unit operated from the Salon and Clermont-Aulnat air bases.
By May 1940, 13 aircraft were operational with Eskadra Koolhoven.  As delivered, however, the fighters were unarmed and the Poles had to acquire machine guns and fit them. From 30 May 1940, they were in service, patrolling firstly in the Avignon-Marseille area, and then over Clermont-Ferrand. At least 47 operational sorties were recorded, but the Escadron did not encounter enemy aircraft.
The type's service life was short-lived, with ; the unit had no confirmed victories, but at least one F.K.58 was lost. After the fall of France, all surviving airframes were scrapped.
Koolhoven F.K.58