The rider was hit on the tracks alongside Harbor Drive near Sampson Street around 5:45 a.m., San Diego police Officer Frank Cali said. It was not clear how many passengers were aboard the trolley at the time.
Emergency personnel attempted to revive the cyclist, but he died at the scene, Cali said. His name was not immediately released.
Police said that the 27-year-old man, waited at the trolley crossing while a southbound trolley passed. He then went past a lowered crossing arms and was hit by a northbound trolley. Witness said he was wearing earbuds and may not have heard the second trolley as it approached .
The Metropolitan Transit System, which operates the trolleys, announced via Twitter that its blue line trolleys were running up to 30 minutes behind in both directions. Police have closed Harbor Drive in the vicinity of the crash and advised motorists to use an alternate route.