Sirena underwent a $40 million refurbishment in 2016 to elevate the ship to the Oceania Cruises’ standard of elegance. She features Oceania's renowned specialty dining restaurants, Toscana and Polo Grill and much more. Sirena passengers tend to be Discerning 40+ and Mainly American. When all cabins have double occupancy, the ship provides a space ratio of 44.3 tons per passenger and a crew to passenger ratio of one for every 1.8 passengers. At full capacity the space ratio is 36.7 tons per passenger and the crew ratio is one to 2.2 passengers.