"I'm good," he told reporters after U.S. Secret Service Agents quickly helped him up. "I got my foot caught" in the toe cages.
Biden, 79, and first lady Jill Biden were wrapping up a morning ride when the president decided to pedal over to a crowd of well-wishers standing by the bike trail. Biden, who was wearing a helmet, tumbled when he tried to dismount.
The president quickly collected himself and spent several minutes chatting with people who had gathered to watch him bike.
The Bidens are spending a long weekend at their Rehoboth Beach home. They marked their 45th wedding anniversary on Friday.