I remember back when I was on a Panama canal cruise a Catholic priest said that he was going to be on the ship for his holidays and on the Dis posted that he would be open to saying Mass. He was put into touch with
DCL about it and there was a daily mass in the movie theater, however most people attended on Sunday's. Otherwise the crew said that they usually have a weekly multi faith service that people can attend on longer cruises that is usually lead by a crew member.