At the 2008 Summer Olympics in Beijing, Reynisson qualified for the second time in the 100 m butterfly, by eclipsing a FINA B-standard entry time of 54.32 from the Mare Nostrum Monte Carlo Meet in Monaco. Reynisson challenged seven other swimmers on the third heat, including three-time Olympians Jeremy Knowles of the Bahamas and Camilo Becerra of Colombia. He edged out Becerra to take a fifth spot by a single tenth margin (0.10), posting his lifetime best of 54.17, just 0.15 of a second faster than his entry time. Reynisson failed to advance into the semifinals, as he placed fifty-second out of 66 swimmers in the preliminary heats.