At the 2008 Summer Olympics in Beijing, Gambin competed for Malta in the men's 100 m butterfly. Swimming on the outside lane in heat four, Gambin maintained an impressive run throughout the race, as he lowered again his lifetime best and Maltese record to 53.70 seconds on a tech bodysuit to finish sixth and forty-eighth overall on the evening prelims, but his most satisfying mark was not enough to put him through to the top 16.