The Coast Guard says search and rescue crews received a call about the accident near Boston Light at around 6:15 p.m. Saturday.
State police spokesman David Procopio says two men were thrown into the water after the roughly 30-foot speedboat broke apart and flipped over. He says one suffered a head injury and the other a chest injury.
Procopio says one of the passengers was pronounced dead at the scene, while the other was taken by helicopter to a Boston hospital. Authorities haven't released the identities of the passengers.
The cause of the accident is under investigation.
