TOKYO—The $500 million cruise liner that became an incubator for the novel coronavirus will resume service again soon with its next group of holidaymakers, according to its operator, though only after a thorough cleaning.

At its dock near Tokyo, the Diamond Princess still houses some passengers and crew under quarantine for the virus, two weeks after their voyage was scheduled to have ended. A barrage of publicity about the ship and its more than 600 coronavirus patients made it one of the most famous, or infamous, cruise...