Abstract: Disclosed is a process for obtaining a flexible conduit comprising a tube and a helical structure. The process comprises extruding a crosslinkable plastic material in a malleable or formable state, so as to form a profiled strip having, as one piece, a web with two mutually complementary marginal edges, and at least one rib projecting on one side from the web; winding the profiled strip about an axis in a helix with touching turns so that the complementary marginal edges of the profiled strip, belonging respectively to two different turns, form between them, directly, a sealed joint; varying and controlling a winding pitch of the profiled strip, in order to modulate and control a quantity of available and formable plastic material of the tube along the length of the conduit; and crosslinking the wound profiled strip.