About 240 miles west of Socorro lies another body of land, the second largest in the Revillagigedo Islands. Formerly named Santa Rosa, it was renamed Clarion Island after the American brig "Clarión" in the early 1800s.

Isla Clarion is little over five miles long and two miles wide. With three volcanic peaks, rolling landscape and rocky, perpendicular cliffs, it looks much like Socorro Island. There is a bay called Sulphur Bay on the south side of the island.

The Clarion Angelfish is named after Clarion Island but is seen all around Revillagigedos. As a juvenile it has bright blue bands that fade away as the fish matures. It is generally considered to be an endemic species to the Revillagigedos archipelago. Adults are commonly seen cleaning parasites from the giant manta rays.