Pontin began his career with Cardiff City, making nearly 200 league appearances and earning two caps for the Welsh national team.
Born in Pontyclun, Pontin began his career at Cardiff City, working his way through the youth system before making his debut in a 2–0 victory over Charlton Athletic on the opening day of the 1976–77 season.
He returned to the reserves shortly afterwards due to the arrival of Paul Went from Portsmouth but was eventually recalled in September 1977 when Went was moved into a more attacking role.
It was at the start of the following year that things turned sour for him at Ninian Park when he fell out with manager Len Ashurst after an argument and was allowed to leave the club to join Merthyr Tydfil.
In his later years with Barry, he was appointed club captain and also briefly acted as assistant manager under Mel Donovan before leaving in 1991 having made more than 200 appearances in all competitions.