Abstract: An optical cable (1) comprises a cable sheath (11) and at least two optical transmission elements (101) and (102), which are arranged within the cable sheath (11). One (101) of the optical transmission elements (101) and (102) comprises a buffer tube (1011), at least one optical waveguide (10101) and at least one swelling element (10111). The buffer tube (1011) surrounds the at least one optical waveguide (10101) and the at least one swelling element (10111). The swelling element (10111) comprises a swelling material, which can swell by supplying it with water. If water penetrates into the optical transmission element, the swelling element (10111) swells and seals off the optical transmission element, so that spreading of the water in the longitudinal direction of the optical transmission element is prevented.