Princess Cruises has pleaded guilty to a second violation of probation imposed in a 2017 criminal conviction for environmental crimes because it failed to establish and maintain an independent internal investigative office, the U.S. Department of Justice announced.

In a statement Jan. 12, the department said Princess was ordered to pay an additional $1 million and will be required to undertake remedial measures to ensure the cruise line and its parent company, Carnival Corp., establish and maintain an independent investigative office.

“Princess admitted that internal investigators had not...