He turned pro in 1983, spending most of the 1983–84 season in the AHL, where he notched 25 goals in 60 games for the Fredericton Express.
[citation needed] Lanthier continued to produce well in the AHL in 1984–85, earning another 27 games with the Canucks, in which he scored 6 goals and 10 points.
For 1986–87, he found himself back in the AHL and suffered through a miserable year in which he recorded just 15 goals and failed to see any NHL action.
He spent the final two seasons of his career with the Utica Devils, New Jersey's AHL farm team, before retiring in 1990.
[citation needed] Lanthier finished his career with 16 goals and 16 assists for 32 points in 105 NHL games, all with the Vancouver Canucks, along with 29 penalty minutes.