  Quantum key distribution (QKD) based on entangled photon pairs holds the
potential for repeater-based quantum networks connecting clients over long
distance. We demonstrate long-distance entanglement distribution by means of
polarisation-entangled photon pairs through two successive deployed 96 km-long
telecommunications fibres in the same submarine cable. One photon of each pair
was detected directly after the source, while the other travelled the fibre
cable in both directions for a total distance of 192 km and attenuation of 48
dB. The observed two-photon Bell state exhibited a fidelity 85% $\pm$ 2% and
was stable over several hours. We employed neither active stabilisation of the
quantum state nor chromatic dispersion compensation for the fibre.
