Fares per person start at €131 on Costa Diadema and €141 on Costa Serena. Costa Diadema is the bigger ship, carrying 3,724 guests to 3,014. Costa Serena has the fewest guests per crew member, at 2.7 to 1. Costa Diadema is newer, built in 2014 against 2007, though Costa Serena was refurbished in 2025. Costa Diadema runs 1–27 night cruises from Santos and Kiel, plus 20 other ports, while Costa Serena runs 1–61 night cruises from Marseille and Buenos Aires, plus 19 other ports.
