Jemima competed in 11 events, eight individuals and three relays, and reached the finals of the 50m, 100m and 200m butterfly and the 200m individual medley.
With an outstanding performance in the butterfly events she won bronze medals in the 50m and 200m and silver in the 100m.
She also won a bronze in the mixed 4x100m freestyle relay and silver in the individual medley with both the 4x50m and the 4x100m relay teams.
The competition featured 138 swimmers from 19 different countries and Team GB finished as the best team in Europe, allowing Jemima to return brimming with self-confidence.
She said: “My goal was to get into a final or two. I am amazed to come home with three individual medals and 3 relay medals.
“I feel stunned. My highlight was my silver medal in the 100m ‘fly – and being with my friends.”
Coach Della Clout added: “I am very proud of Jemima’s growth and approach to her racing. She’s using her training in the pool and understanding her goals better. She did a great job.”