On 31 October 2020 he made his England debut from the bench in England's delayed final Six Nations match against Italy, to become the 2020 Six Nations champions.[4]
In January 2023 Dunn was called into the England Six Nations' training squad as an injury replacement.
Dunn was Bath’s top try-scorer in the Premiership in the 2022–23 season, recording 12 tries, including a memorable hat-trick against Saracens in the final game of the season.[5]
In 2023, Dunn celebrated a milestone by reaching 200 appearances for Bath Rugby, becoming one of 10 players to achieve the career landmark in the professional era, joining the likes of Nick Abendanon, Olly Barkley, David Flatman and Matt Banahan.[6]