Kieran Bird is a middle distance freestyle specialist. He made his senior international debut at the 2020 European Aquatics Championships in Budapest, racing in the 400m and 800m freestyle events.

Bird realised a lifelong ambition by representing Team GB at the 2020 Tokyo Summer Olympics, competing in the heats of both the 400m and 800m freestyle. His career reached a new milestone in Paris, where he won Olympic gold as a heat swimmer in the British 4×200m freestyle relay at the 2024 Summer Olympics.

Representing Wales at the 2022 Commonwealth Games, Bird also reached the final of the 4×200m freestyle relay, finishing fourth. In the same year, he won a gold medal as part of the Great Britain 4x200m mixed freestyle relay team at the 2022 European Aquatics Championships in Rome.

In 2024, Bird captured the 400m freestyle title at the Aquatics GB Championships in a personal best time of 3:45.63. This performance ranked him the third-fastest British swimmer in history over the distance, cementing his status among Britain’s elite middle-distance freestyle swimmers.