Carnival Cruise Lines says the ship, Carnival Ecstasy, had to make a sharp turn to avoid the buoy Wednesday afternoon.
Carnival spokeswoman Jennifer De La Cruz says 60 guests suffered minor injuries and that some unsecured objects aboard the ship were damaged. She says no one required treatment at a hospital.
The U.S. Coast Guard has been notified about the wayward buoy.
Miami-based Carnival said the ship safely docked Thursday at its home port in Galveston.
Passenger Patrice Edwards told KHOU-TV that she was thrown out of bed as "the whole boat just shifted."
Information assist from: KHOU-TV, http://www.khou.com
