In countries which have to deal with the electrical energy supply to several and small islands, wind farms, oil wells and other users by the sea, a local power production is often not possible, not convenient or with a low efficiency. For these reasons in the last century, and above all in the last decades with a growing interest from the research field, the employment of submarine power cables to provide electrical power to the less accessible users is increasing. After the installation, the main problem for these systems is their life expectation, thus the study of their creep-fatigue behaviour. The life of these cables, which is determined by the most critical layer (the water-blocking Pb sheath) was incremented in several ways: from the alloys’ composition choice to the realization of other layers.