Sycerika McMahon (born 11 April 1995) is a retired Irish swimmer from Portaferry, County Down.

[2] At 17 she became the youngest Irish medal-winner in a major event when she took silver in the 50 metre breaststroke at the 2012 European Aquatics Championships in Debrecen, where she also set a new Irish record.

[6] In the 2012 European Short Course Swimming Championships in Chartres she won bronze in the 50 m breaststroke behind Petra Chocová and Rikke Møller Pedersen.

[8] In her Freshman year she became the second-fastest A&M Aggie ever in the 100 yard breaststroke when she finished fourth in the event at the SEC Championships with a time of 59.35 seconds.

[9] McMahon announced her retirement from the sport on Instagram in June 2017, aged 22.