Biden and his wife, Jill, will first attend a morning ceremony in lower Manhattan in New York, where al Qaeda hijackers flew two airplanes into the World Trade Center’s twin towers.
Republican Vice President Mike Pence will also be on hand for the ceremony.
Trump will speak at a morning ceremony at the Flight 93 National Memorial in Shanksville, Pennsylvania, a White House official said.
The event, in remembrance of the 40 passengers and crew who died when the plane plunged into a field after they struggled with the hijackers, will be closed to the public because of coronavirus concerns, the National Park Service said.
Later in the day, the Bidens will visit the Shanksville site to pay their respects to the victims.
The two candidates were not expected to cross paths in Pennsylvania, a battleground state that is vital to the Nov. 3 election between Trump and Biden.
Flight 93, bound for San Francisco from Newark, New Jersey, never hit its intended target — the four hijackers were believed to be planning to crash it into either the United States Capitol or the White House — after passengers stormed the cockpit and attempted to regain control of the aircraft.
In all, nearly 3,000 people died in the Sept. 11, 2001, attacks, which also included a fourth hijacked plane that slammed into the Pentagon outside Washington.
The ceremonies marking the attacks are a regular stop for presidential candidates and officials.
Trump visited Shanksville for the 9/11 anniversary in 2018, and has attended memorial ceremonies at the Pentagon.
Biden went to memorials in Shanksville during his years as vice president under Barack Obama.
During the 2016 presidential campaign, Trump and Democratic presidential candidate Hillary Clinton both visited the Ground Zero memorial in New York on the anniversary of 9/11.
Biden’s campaign said it was pulling its television ads off the air on Friday to commemorate the anniversary of the attacks.
The nonprofit 9/11 Day had asked both campaigns to pull its ads.
The Trump campaign did not respond to requests for comment on whether it would do so.
