Carnival boasts largest market share of cruise passengers
http://marketrealist.com/2015/01/key-overview-carnival-worlds-largest-cruise-company
Carnival Corporation is the largest with a market share of cruise passengers at ~47%, followed by Royal Caribbean at ~23% and Norwegian at ~10%. However, Carnival’s competitive advantage is due to scale. It operates a fleet of 101 ships, which is more than double the 41 ships operated by Royal Caribbean, its closest competitor.