As a member of the Australasia combined team of Australia and New Zealand athletes, Boardman won a gold medal in the 4×200-metre freestyle relay at the 1912 Summer Olympics in Stockholm, Sweden.

[1] Although little is known about Boardman, he never won any Australian championships and was not among the original selections for the Stockholm Olympics.

It is hypothesized that he was chosen because he was a teammate at the Sydney Swimming Club of Harold Hardwick and Cecil Healy.

Boardman competed in the 100-metre freestyle at the Stockholm Olympics where he won his heat, but came fourth in the second round and was eliminated.

In the 4×200-metre freestyle relay, he swam the third leg as the team of Hardwick (Australia), Healy (Australia) and Malcolm Champion (New Zealand) defeated the United States team for the gold medal.