An optical cable for communication includes at least one retaining element blocked with respect to the water propagation as well as a process for manufacturing such an optical cable. The optical cable includes, in addition to the retaining element, at least two transmission elements housed within the retaining element and a water swellable yarn housed within the retaining element. The water swellable yarn is selected according to the following equation: V w V TF = k V t + R ( 1 ) in which Vw is the volume of the water swellable yarn after swelling upon contact with water; VTF is the total free volume in the retaining element; k is a constant ≧180; R is a constant ≧1.4; and Vt is the free volume per each transmission element. Advantageously, the optical cable is water-blocked and the water swellable yarn does not induce microbending effects on the transmission elements.