Parkrun race director Sally Coyle confirmed 659 people descended on Lake Burley Griffin at Yarralumla for Parkrun before heading home to enjoy a guilt-free Christmas feast.

Ms Coyle was thrilled they had broken Canberra Parkrun attendance records.

Paul and Philippa Wood pulled out all the stops in their matching Santa costumes, but were grateful for an overcast and cool morning.

"[The outfits] are a little bit warm ... we are quite appreciative of the weather. We started it a couple of years ago and thought why not keep it going," Ms Wood said.

"But they're not the most breathable of material."

The couple are avid parkrunners, keeping up the tradition together when organised events for cancelled for much of 2020 due to COVID-19 and bushfire smoke. The Christmas event was one of the best, and biggest, of the year.

"It's lovely to get up early in the morning ... everyone [wears] a costume, it's a bit of fun and brings Christmas spirit alive," Ms Wood said.

"Particularly this year, it's great to see all these people here together, it's fantastic," Mr Wood added.

The Barlow family have been doing Parkrun together for six years, for William Barlow it's all about the run but for Kristie Barlow, it's the community that comes along with that.

"You do Parkrun on Christmas Day and then you can do whatever you like. You can sit on the couch, you can eat whatever you want, you've run five kilometres, you're good to go," Mr Barlow said.

"[Christmas] is not just about food and presents, it's about community. It's good to start the day on a good note."

Although the run delayed the Christmas present opening, April Barlow, 9, was eager to come down to catch up with the many dogs that joined in the fun. A pair of Jack Russells dressed for the occasion in matching elf costumes were a crowd favourite.

After a six-month hiatus, Parkrun made a comeback at the end of October and Ms Coyle said everyone was keen to jump back in.

"Everyone was pretty excited to come back and see all their old friends, we had a lot of people hovering on their 49th and they wanted to get their 50th Parkrun," she said.

Coronavirus rules were in place for the event, with people spreading out where they could and checking in using a government app.