Lucas was chosen to compete for Great Britain at the 2012 Summer Paralympics, again in the 2.4 mR – 1 person keelboat event. She was the last member of the British sailing team to be selected after the announcement of the 2.4 mR representative was delayed because of the close competition between Lucas and Megan Pascoe. At the Games she was the only woman in the fleet of 16 sailors who contested the event. Heading into the final race she was in first place and held a nine-point lead over second-place sailor Heiko Kroger of Germany, which meant she was guaranteed at least a silver medal. Due to a lack of wind the races on the final day of competition were cancelled, meaning Lucas won the gold medal. She became the first British sailor ever to win a Paralympic gold medal.