A floating structure intended for the deployment or the recovery of at least one autonomous watercraft in aquatic environment, the autonomous watercraft having an elongated hull and comprising a keel, the autonomous watercraft being able to move in the aquatic environment at least in a surface configuration in which it floats at the surface of the aquatic environment, the floating structure being intended to be launched and to be recovered by/on a vessel, wherein the floating structure is longitudinally elongated from the rear to the front and comprises a hull with an underwater hull, the underwater hull corresponding to the immersed part of the hull, the floating structure comprising floating portside lateral edge and starboard lateral edge and a submersible bottom connected to the two lateral edges, the submersible bottom being immersed when the floating structure is in the water, the two floating lateral edges (13, 14) and the submersible bottom defining an interior space of the floating structure, the interior space being at least partly submerged when the floating structure is in the water, the two floating lateral edges (13, 14) joining each other on the front of the floating structure to form a bow, and the two rear ends of the floating lateral edges (13, 14) being separated by an opening towards the rear of the floating structure, the opening being limited downward by the submersible bottom, and the submersible bottom further comprises at least one longitudinally elongated slot open towards the rear and intended for the passage of the keel of the autonomous watercraft and the floating structure is configured so that at least the front part of the autonomous watercraft comprising the keel can engage by floating into the interior space, with the keel engaging into the slot, the front of the longitudinally elongated slot of the submersible bottom being closed and forming a stop for the keel of the autonomous watercraft in order to limit the engagement of the autonomous watercraft into the interior space of the floating structure, characterized in that the floating portside and starboard edges are consisted of at least one elongated inflated bladder extending on each lateral side of the floating structure, from the rear to the front of said floating structure, and in that the underwater hull of the floating structure comprises a stem that extends substantially vertically, from the floating line of the floating structure down to the depth of the submersible bottom forming a cutwater joining a portside part and a starboard part of the hull, and, at the lower end of the stem, the portside and starboard parts of the hull are concave, viewed from the water, forming a ridge facilitating the penetration into water and helping maintaining the heading of the floating structure. and in that the underwater hull of the floating structure comprises, in front part, at least one water intake in communication with said interior space and the aquatic environment of the floating structure. wherein the floating structure is longitudinally elongated from the rear to the front and comprises a hull with an underwater hull, the underwater hull corresponding to the immersed part of the hull, the floating structure comprising floating portside lateral edge and starboard lateral edge and a submersible bottom connected to the two lateral edges, the submersible bottom being immersed when the floating structure is in the water, the two floating lateral edges (13, 14) and the submersible bottom defining an interior space of the floating structure, the interior space being at least partly submerged when the floating structure is in the water, the two floating lateral edges (13, 14) joining each other on the front of the floating structure to form a bow, and the two rear ends of the floating lateral edges (13, 14) being separated by an opening towards the rear of the floating structure, the opening being limited downward by the submersible bottom, and the submersible bottom further comprises at least one longitudinally elongated slot open towards the rear and intended for the passage of the keel of the autonomous watercraft and the floating structure is configured so that at least the front part of the autonomous watercraft comprising the keel can engage by floating into the interior space, with the keel engaging into the slot, the front of the longitudinally elongated slot of the submersible bottom being closed and forming a stop for the keel of the autonomous watercraft in order to limit the engagement of the autonomous watercraft into the interior space of the floating structure, characterized in that the floating portside and starboard edges are consisted of at least one elongated inflated bladder extending on each lateral side of the floating structure, from the rear to the front of said floating structure, and in that the underwater hull of the floating structure comprises a stem that extends substantially vertically, from the floating line of the floating structure down to the depth of the submersible bottom forming a cutwater joining a portside part and a starboard part of the hull, and, at the lower end of the stem, the portside and starboard parts of the hull are concave, viewed from the water, forming a ridge facilitating the penetration into water and helping maintaining the heading of the floating structure. and in that the underwater hull of the floating structure comprises, in front part, at least one water intake in communication with said interior space and the aquatic environment of the floating structure.