Transmediterranean balloon flights are made with zero-pressure stratospheric vehicles, that contain scientific experiments on board. The balloons are released during summer in Sicily, Italy. Eastern stratospheric seasonal winds transport them over the Mediterranean and the flight termination by telecommand and recovery is accomplished in Spain. The paper addresses a thorough description of the program, which was initially conceived to extend the flight time over the existing national options (Air-sur-l’Adour, Gap Taillard, Trapani, León), considers several flight support subsystems and gives hints for their future improvement, though the main focus is on the balloon operations.