The US Institute of Peace published on 30 January 2024 a commentary titled "Is China Eyeing a Second Military Base in Africa?" by Alex Vines, Henry Tugendhat, and Armida van Rij.
China opened in 2017 a military base in Djibouti. Rumors persist that it plans to establish another base in Africa. The authors conclude that China is more likely to expand existing civilian port infrastructure and build dual use facilities in African ports where it has already invested than to construct another military base.
Comment: The commentary indicates that Saudi Arabia has a military base in Djibouti. While press reports have suggested for several years that Saudi Arabia plans to locate a military base there, I am not aware of any proof that it has actually done so.