Joe played for Burry Port and Coleg Sir Gar and before being capped for Wales U18s. Spent a spell on loan with Ampthill RFC in 2021 before playing in the end-of-season Rainbow Cup for the Scarlets. Made a big impression during a breakthrough 2021-22 and after recovering from a knee injury, Roberts made a huge impact at the start of 2023, becoming a first-choice centre pick at the Scarlets and earning a first Wales call-up as part of the World Cup training squad. Has become a regular in the Scarlets midfield and Welsh squad in recent years and finished the 2025-26 campaign as the club’s leading try-scorer, earning a recall for the Summer Nations series.