System (1, 2) (1, 4) for handling marine or underwater drones for the launching or recovery of said marine or underwater drones, wherein the system (1, 2) (1, 4) is able to float on water and includes a floating pontoon and a number of interchangeable drone interface modules (2, 4), wherein the pontoon is consisted, in lower portion, of two shells, and in upper part, of an arch bridging the two shells, each shell including towards the bottom a hull topped with an out-of-water area, the arch being secured to the out-of-water area of the two shells, wherein the pontoon is a catamaran-shaped structure longitudinally elongated between a front end and a rear end, the two shells being longitudinally elongated and parallel to each other, delimiting between them and with the arch located above a reception space that is open on the front and on the rear, said reception space being longitudinally elongated and submerged at the bottom, each shell having an inner face located on the side of the reception space, an outer face, an upper face, a lower edge, a front end and a rear end, the pontoon being symmetric with respect to a sagittal plane, and wherein the arch includes at least one attachment device for attachment to a winch cable for raising up the pontoon out of water or, conversely, lowering down the pontoon for launching, wherein the pontoon includes devices for removable fastening to each one of the drone interface modules (2, 4) installed in a removable and interchangeable manner in the reception space, the drone interface modules (2, 4) being open for the passage of a drone (3, 5) at least at one of their two ends and being hollow and forming a longitudinally extended and at least partially submerged docking area (23, 42) for a drone (3, 5), wherein a marine drone floating at the surface or an underwater drone diving near the surface can enter the docking area (23, 42) of the drone interface module (2, 4) installed in the reception space, or, conversely, exit therefrom when the pontoon and its drone interface module (2, 4) are at water and wherein the drone interface modules (2, 4) have a lower portion (22, 43) and are configured to rest stably with their lower portion on a flat surface once the drone interface module (2, 4) disassembled from the pontoon, and characterized in that one of the drone interface modules of the system (1, 4) is open towards the rear and is closed towards the bottom, towards the top and towards the front, said drone interface module being a longitudinally elongated cage able to be inserted into the reception space of the pontoon, said cage being consisted of an assembly of metal rods delimiting a substantially tubular inner housing forming the docking area and in which inner housing an underwater drone can be inserted and retained, said cage comprising a stowing shield arranged on the rear of the cage in the absence of drone in the cage, the stowing shield being able to slide in the inner housing from the rear to the front, and conversely, the front of the drone being able to be removably secured to the stowing shield, the drone secured to the stowing shield and said stowing shield moving together within the inner housing.