Jason Robert Plummer (3 March 1969 – 15 November 2021) was an Australian freestyle swimmer, who competed at the 1988 Summer Olympics in Seoul.

At the 1985 National Championships he won silver in 400m, 800m and 1500m freestyle finishing behind fellow Queenslander Michael Bruce McKenzie in all three events.

The following year at the Edinburgh Commonwealth Games he won his pet event, the 1500m freestyle, over McKenzie and Christopher Chalmers from Canada.

In 1987 Plummer won the Surf Race Championship of Australia at Scarborough Beach, WA.

Plummer sold luxury real estate in the Southlake and Westlake areas of Dallas Fort Worth in the United States.