But instead of running the 26.2 miles around the capital with a mass start, encouraged by the hundreds and thousands of spectators along the route and then crossing the finish line in front of Buckingham Palace, they will experience the loneliness of a long distance runner.
The coronavirus has robbed the competitors of their London marathon experience and local restrictions across the Welsh border have meant many have had to make last minute changes to their routes.
Vicky Thompson, from Coalbrookdale, is the first person ever to run the marathon for Telford charity Race Against Blood Cancer after the charity succeeded for the first time in getting a runner through the ballot system.
She had been training hard before the physical marathon was cancelled in April, and the mother-of-four has had her hands full at home over lockdown.
"Whatever I'm going to do, it will be a PB," she said.
Race Against Blood Cancer's chair of trustees Joe Bates will run the first 10k with Vicky. Her complete route covers central Telford, Coalport, Bridgnorth and Ironbridge before finishing in Coalbrookdale.
A foursome of Newport & District Running club members will be racing around their town and the surrounding villages in pairs.
Joanne Lutner and Simon Yap will depart from the Stafford Street car park at 9am, touring Church Aston, Lilleshall and Edgmond before returning to the centre of Newport. At 11am Phil Dolding and Rodney Jones will set out on the same circuit, and each pair will do the entire loop three times.
Sally Johnson has deferred her official place to 2021 or 22 but will use her training to put in an extra marathon around the streets of Shrewsbury on Sunday for her 2020 challenge for The Harry Johnson Trust, Make a Wish UK and Children With Cancer UK.
Those running around Lake Vyrnwy for their route - a popular half marathon takes place there each year, are being warned that part of the circular route is still closed to traffic after storms and reminded of dangers from traffic and to stay socially distanced.
More than two dozen members of the Oswestry based, Girls on the Run group are taking part in the Virtual London Marathon with many having planned to run on the canal to Llangollen and back.
Welsh restrictions have scuppered the route and now they are looking at around Oswestry and Ellesmere routes.