With only eight weeks till the rescheduled festival date of November 8, race director Julie Tedde said it was too unlikely restrictions would ease enough to allow a mass participation event. Instead, a "virtual event" would be held in its place.

"We were aware early on in the year that holding a mass participation event was not likely," Ms Tedde said.

"We were definitely optimistic, even a month ago, that the event would proceed.

"As much as certain things are moving along and opening up, outdoor events [are] just being held at under 100."

A statement from race organiser Sole Motive said it had worked closely with the ACT Health Department, NCA and Access Canberra to try to find a suitable way to run the festival.

Registered participants for the 2020 event will be automatically transferred to the 2021 Marathon which is expected to go ahead on April 10-11 next year.

Meanwhile for avid runners who were excited for this year's event, there will be a virtual marathon held between November 7-15 2020.

Sole Motive has previously run a successful virtual marathon in Melbourne.

Participants can run the race individually any time between November 7-15, track their time and receive medals and rankings.

"You then submit that to a link and that goes to a proper results page so then we produce results with that in there with the event," Ms Tedde said.

Festival organisers believe it's important to give seasoned and budding runners opportunities for competitions and training even if the marathon festival cannot go ahead as normal.

"We are very conscious that the running community, they were training along for something, they are on a journey of preparing themselves," Ms Tedde said.

"Anyone who is entered already will be put into that event for free. Anyone else who would like to enter the event they will be able to do so on our website."

The marathon has three options for new registrations, ranging from $15-55.

Canberrans have until November 4 to register for the festival.

Race attendees can choose to run races from 2k, 5.4k, 10k, 21.1k. 42.2k, 50k, and can run or walk anywhere for the festival.

Runners can even participate in the virtual festival on a treadmill.

All finishers who upload their results by November 15 will receive a certificate on November 16.

"We feel we're offering a lot to people who haven't entered the event yet but we are also valuing the participants who have entered by giving them the complementary entry into [the virtual marathon festival].

"You can't run together with the big running community that we know that people love, that we love but we feel that we can still keep you together by doing this."