In 2552, Coral Sea saw action at the Battle of Earth in the Battle of Mombasa. She, the UNSC Dusk, UNSC Paris and UNSC Redoubtable were the only ships fast enough to be able to pursue the UNSC In Amber Clad and the High Prophet of Regret's Assault Carrier into Slipspace. Coral Sea quickly outran the Dusk during the chase.
Once the Coral Sea made it through to Installation 05, it hid near the surface of the ring in order to avoid Covenant detection. It spent huge portions of its time scanning the various components of the ring. This includes the sites known as "Ascension", "Beaver Creek", "Coagulation", "Desolation", "Sanctuary", and "Uplift".
- The Coral Sea may be named in reference to the Battle of the Coral Sea, a World War II naval battle in May 1942 in which the American navy was able to halt and completely deter Japan's attempt to invade Australia from New Guinea.
- Halo: Ghosts of Onyx (First appearance)