"The agreement is in preparation for the completion of the fibre optic installation which will be operational by the end of the year," Development Minister Samura Kamara told local radio.
"It will enable every Sierra Leonean to benefit from the international fibre connection from Paris to the landing site in Freetown through South Africa which will involve Guinea and Liberia."
Chinese Ambassador Kuang Weilin said "the agreement is keeping to the bilateral and development cooperation" between the two states and will be implemented by Chinese telecommunications giant Huawei.
The 17,000-kilometre-long (10,540-mile) submarine cable runs from Cape Town along the west coast of Africa, through Portugal and to France, connecting 21 countries, 18 of which are in Africa.
The cable was laid in Sierra Leone with the assistance of a $31 million load from the World Bank, and is expected to reduce the west African nation's dependence on expensive satellite bandwidth for internet connections.