Diving dry suit

Diving dry suit comprising a watertight first part (2) forming, in one watertight piece from top to bottom, a chest portion (12), trousers (22) and socks (32), and a separate second part forming a watertight jacket (3), wherein the watertight jacket (3) comprises an interior layer (13) and an exterior layer (23), the interior layer (13) being in watertight material and comprising a chest portion and long sleeves, the interior layer (13) being also provided with watertight cuffs (113, 213) at the neck and at the end of the sleeves, the exterior layer (23) of the watertight jacket (3) also comprising a chest portion and long sleeves, the interior layer (13) and the exterior layer (23) being separate entities separably fastened together at the level of at least one valve (4, 5) allowing transfer of gas between the space between the body of the user and the interior layer (23) and the exterior of the suit, the suit being free of any watertight zip opening/closing system, and in that the central portion of the first part (2) and the lower portion of the interior layer (13) of the jacket (3) each comprise an elastic waterproof material skirt (72, 313) to allow their conjoint watertight rolling so as to produce a watertight connection between the jacket (3) and the first part (2).