Staff from The Exercise Lounge will join Katharine House Hospice’s event in the town’s Spiceball Park on December 1.
The 1.5km or 5km run will raise funds for the hospice, which supports people with life-limiting illnesses.
Caring for around 1,300 people, it is available to a population of 275,000 in north Oxfordshire and south Northamptonshire.
Lana Petrie, manager of The Exercise Lounge, will lead the warm-up on the day.
She said: “Doing the warm-up for this event is something I’m really excited for, as I’ve wanted to do it for years.
“I’ve been working on different social events for all of the members at The Exercise Lounge, a local gym that I am the manager of.
“And what better way than to do something that is fun for us, but also for a really good cause.”
Helen Lerwill, from Katharine House Hospice, added: “Our Santa fun run is a great way to kick off the festive season and we can’t wait to welcome The Exercise Lounge and the other hundreds of Santas taking part.
“We’d also like to thank this year’s sponsors; Norbar, Hayfield Homes, David Wilson Homes and Barratt Homes for helping to fund the event.
“We’re delighted to be working with them and incredibly grateful for their support.”