The charity provides first aid on contract to Oxford United and London Welsh RFC, with the matches covered by volunteers.
Now, St John says it wants a dedicated unit to allow volunteers to work more closely with match day officials.
Area manager Andrew Frost said: “Anyone volunteering to be a first aider at the Kassam Stadium will have the benefit of seeing some of the matches.
“However, a first aider must be alert at all times to the medical needs of those around them, so anyone interested in joining must have first aid at the forefront of their minds.
“I can certainly say that being a St John Ambulance volunteer is extremely rewarding and it’s great to be able to give something back to your local community.
“You could be the difference between a life lost and a life saved.”
Volunteers provide first aid for anything from sprains and strains to heat exhaustion and heart attacks.
In particular, a manager is required for the new unit along with other more senior roles.
All first aid training will be provided by St John Ambulance, so no previous medical experience is required.
For more information, visit sja.org.uk, email email@example.com or call 0303 003 0101.