Because of the coronavirus, officials at the Boston Marathon announced the 124-year-old race will go on, but in September.

Boston officials announced on March 13 during a press conference that the 2020 Boston Marathon will be postponed until September 14, rescheduled from April 20 amid concerns about COVID-19 (“coronavirus”). On Wednesday, the Boston Athletic Association released details about how they’ll cope with 2020 race registrations for runners who opt not to participate in September.

Runners entered in the 2020 race can  either compete in the event on September 14 or receive a refund. Those who decide to have their registration fees refunded must request it by May 29. The 2020 Boston Marathon will also serve as a qualifier for 2021—registration for the 2021 Boston Marathon will take place sometime after September 14, officials said.

“Our primary focus remains on the health and well-being of participants, staff, volunteers, spectators, supporters, and everyone in our greater community,” said Tom Grilk, Chief Executive Officer of the B.A.A., in a written statement. “We’d like our entrants to join us in September. However, while we are in the midst of the evolving COVID-19 pandemic, we want to extend an offer of refund to our entrants so they may be able to plan accordingly.”

The state will declare September 14 a holiday, tentatively called “Marathon Day,” just like the spring Monday is Patriots’ Day in Massachusetts.

The London Marathon has also been rescheduled from April 26 to October 4, the organizers announced on Friday. Runners will be able to choose to use their entry on the rescheduled date, defer entry to 2021, or receive a refund of the registration fee.

“We know that there will be many, many questions from runners, charities and others and we ask you to please bear with us as we work through the detailed planning process to deliver the 2020 Virgin Money London Marathon on its new scheduled date,” said Hugh Brasher, London event director, in a written statement.  “We will email all runners and charities today and then update them via email by the end of next week at the latest. We will also post regular updates on our website and social media channels.”

Boston and London are not the only races grappling with how to proceed during the pandemic. The Tokyo Marathon, which like the Boston Marathon is part of the World Marathon Majors (WMM), decided to hold an elite-only race on March 1—it usually draws a field of more than 35,000 runners. The Rome and Barcelona marathons are also among the races that will not go on this year—other international events, like the world half marathon championships in Poland, have been postponed until the fall.

U.S.A. Track & Field is also rescheduling the 2020 U.S. Olympic Trials, which were scheduled for June, following the postponement of the 2020 Olympics to 2021.

The NYC Half marathon with about 25,000 runners was canceled earlier in March. New York Road Runners officials said in a statement that resources to safely accommodate the large-scale event on the streets of Brooklyn and Manhattan became strained as more residents fell ill with the COVID-19 virus\.

“The NYRR team worked hard to adjust plans, implementing modifications and accommodations to alleviate crowding and facilitate social distancing,” the statement said. “Unfortunately, it has become clear that we will be unable to proceed in the manner that our runners have come to expect at NYRR events, where the safety and security of our runners, volunteers, staff, partners, and spectators are our main concern.”

Runners have the opportunity to receive a registration fee refund or defer their entry until next year.

The Boston Marathon is the oldest annual marathon in the world, which even continued in 1918, though it was modified as a military relay that year because of the country’s involvement in World War I, according to the Boston Globe.