This Recommendation deals with the characteristics of the optical fibre submarine cables used in [ITU-T G.973]@ [ITU-T G.973.1]@ [ITU-T G.974] and [ITU-T G.977]. An optical submarine cable can be used in: ?C a repeatered optical submarine system; ?C a repeaterless optical submarine system. This Recommendation specifies the characteristics of the submarine cables which can be used in the deep and shallow waters. This Recommendation covers: ?C transmission characteristics of optical fibres in submarine cables including mechanical characteristics and resistance to the environment; ?C characteristics of optical fibre submarine cables including mechanical characteristics and resistance to the environment and other electrical characteristics; ?C transmission characteristics of single- and hybrid-fibre type elementary cable sections.