The present invention refers to a shallow diving system in open sea that consists of a main vessel (2) provided with dynamic positioning system (DP) and with the equipments to monitor diving operations, and give assistance and orientation to the divers (6). The main vessel (2) operates with support vessels (3), and together they set the divers (6) and support team at the work location (4), at a safe distance from the main vessel propulsion system, to perform the job on the offshore units (1). These vessels for supporting diving operation, act like satellites of the main vessel, linked to it by means of a umbilical line (5).