At the 2012 Summer Olympics in London, Adrian won his inaugural Olympiad medal, a silver, in the 4×100-meter freestyle relay with Michael Phelps, Cullen Jones and Ryan Lochte, with the team finishing behind France. Swimming the lead-off leg, Adrian recorded a split of 47.89 seconds, and the team finished with a final time of 3:10.38. Adrian's lead-off time was the fastest first leg in the field, and Adrian's inaugural time breaking 48 seconds.