1890 saw Mitchell join William Percy Carpmael's newly formed invitational touring team, the Barbarians; and his Cambridge roots served him well the next season when, after playing all three games of the 1891 Championship, he was selected to join Bill Maclagan's 1891 British Isles team that toured South Africa. He played in all three Test matches, which the tourist won by narrow margins; Mitchell himself scored the only points in the Second Test at Kimberley with a goal from mark. On his return to Britain he was selected for one final international, the 1893 clash with Scotland.