A boat from the Coast Guard's Annapolis station was in the area responding to an unrelated matter when its crew saw the boats collide.
The accident is being investigated by Maryland Natural Resource Police.
Eight people were aboard one of the boats, said Petty Officer 3rd Class Jacob Wieduwilt, the coxswain on the responding Coast Guard vessel, in a statement. Two Coast Guard crewmen boarded that boat to treat the injured while the boat was towed to the Naval Academy pier to meet a local emergency medical team.
One injured boater was airlifted for treatment, another was taken to a local hospital and a third refused additional treatment