Who was Michael Phelps' longtime coach?

Michael Phelps' longtime coach was Bob Bowman. Bowman began coaching Phelps when the swimmer was 11 years old at the North Baltimore Aquatic Club in Maryland, forming one of the most successful athlete-coach partnerships in sports history.

Bowman was known for demanding, highly structured training. He helped Phelps develop across several strokes and events, rather than limiting him to his early specialty, the butterfly. Under Bowman's guidance, Phelps became a world-record holder and the most decorated Olympic athlete ever.

The pair briefly moved to the University of Michigan after the 2004 Athens Olympics, where Bowman became head coach and Phelps trained with the Club Wolverine program. They later returned to Baltimore, and Phelps followed Bowman to Arizona State University in 2015.

A common mix-up is Eddie Reese, another prominent American swimming coach who led the University of Texas program and coached many Olympic swimmers. Reese was influential in U.S. swimming, but Bowman was Phelps' longtime personal coach.