The Co-Optimist Rugby Club is an invitational rugby union club founded in 1924 by Jock Wemyss, the former Scottish test player, together with George St Claire Murray, a rugby enthusiast from the Watsonians club.

[1] The Co-Optimists have played against national fifteen-a-side teams including France, Ireland and Zimbabwe in the 1980s.

[1] The club also has a proud record at the Hong Kong Sevens tournament, finishing as runner-up to Fiji in 1980,[2][3] as a semi-finalist against Australia in 1981, and a quarter-finalist in 1986.

The Co-Optimist badge is a lion couchant in blue on a white background.

Many well-known international players have represented the club including: Finlay Calder, Jonathan Davies, Mike Gibson, Gavin Hastings, Scott Hastings, Andy Irvine, Dickie Jeeps, John Jeffrey, Tom Kiernan, Ian McGeechan, Doddie Weir, Tony O’Reilly and Rob Wainwright.