Abstract: Diving dry suit including a watertight first part forming, in one piece from top to bottom, a chest portion, trousers, and socks, and a separate second part forming a watertight jacket comprising an interior layer being in watertight material and comprising a chest portion and long sleeves, the interior layer being also provided with cuffs at the neck and at the end of the sleeves, an exterior layer of the jacket also comprising a chest portion and long sleeves, the interior layer and the exterior layer being separate entities separably fastened together at the level of at least one valve, the suit being free of any zip opening/closing system, and in that the central portion of the first part and the lower portion of the interior layer of the jacket each comprise an elastic material skirt to produce a watertight connection between the jacket and the first part.