After reaching two finals on an encouraging European Junior Championship debut in 2010, Siobhan-Marie O’Connor burst on to the scene in 2011, winning 200m Individual Medley gold at the ASA National Championships to secure a place at the World Championships in Shanghai.
Before the Worlds, she won three golds (including both individual medleys) and a silver at her second European Junior Championships in Belgrade. She then rose to the occasion on her senior international bow in China, reaching the semi-finals of the 200m IM before finishing 13th.
She booked her place as the youngest swimmer on the London 2012 Olympic team with 100m Breaststroke gold at the 2012 British Gas ASA National Championships, then went on to finish 21st in the 100m Breast and eighth in the 4x100m Medley Relay.
After winning her first major medal with 100m Individual Medley bronze at the 2012 European Short Course Championships in France, O'Connor won her first British medals in 2013 with silver in both the 200m Individual Medley and 50m Butterfly.
At the 2013 World Championships in Barcelona, O'Connor impressed to reach the 200m Individual Medley final before ultimately finishing eighth.
In 2014, she won her first British titles over 200m Freestyle and 200m Individual Medley, then grabbed six medals on her Commonwealth debut for England at Glasgow 2014, including 200m IM gold and silver over 200m Freestyle and 100m Butterfly.