A cable pull-in system and method for offshore structures (1) of the type having a hollow interior extending from the sea bed to above the surface of the water and an entry hole (2) in the external wall of the structure. The system includes an elongated outer conduit assembly (7) within the interior of which is arranged an elongated cable member (10), the elongated outer conduit assembly being equipped with an inflatable sealing section (4) adapted for engaging the interior of entry hole (2) to seal and affix the outer conduit assembly. The elongated outer conduit assembly is pulled through the entry hole and up to a hangoff point above the water surface such that the inflatable sealing section (4) engages entry hole (2).