| Haydn Mainwaring | |
| Full Name: | Haydn James Mainwaring |
| Birth Date: | 10 June 1933 |
| Birth Place: | Swansea, Wales |
| School: | Bishop Gore School |
| Position: | Centre |
| Repyears1: | 1961 |
| Repcaps1: | 1 |
| Reppoints1: | 0 |
Haydn James Mainwaring (10 June 1933 — 12 September 2018) was a Welsh international rugby union player.
Mainwaring was born in Swansea and educated at Bishop Gore School.[1]
A versatile back, Mainwaring played with Swansea, Royal Navy, London Welsh, Harlequins and Newport. He also made several Barbarians appearances, mostly famously as a fullback against the touring 1961 Springboks, with his try-saving shoulder charge on Avril Malan helping secure a 6–0 win.[2] His tackle was described in the press as "like a comet burying itself into earth".[3] He won his solitary Wales cap as a centre in a 1961 Five Nations match against France in Paris.[4]