Two mega-ships are sailing across the Atlantic acting as five-star hotels and playing host for attendees to the United Nations’ COP30 climate conference in Belém do Pará, Brazil.

Costa Diadema (Costa Cruises)
The Ship has left Savona, Italy, on October 24, 2025, with zero passengers. It has just the crew and a mission to serve guests. After a 12-day repositioning voyage, the 2014-built ship drops anchor at Belém’s brand-new Porto do Outeiro cruise terminal on November 4.

MSC Seaview (MSC Cruises)
Seaview departed Barcelona on October 25. She made a quick fuel stop in Las Palmas, and is racing the same deadline. With 4,140 guest capacity, she’ll be the biggest ship in South America this season when she arrives on November 4.

From November 10th to 21st, 2025, both vessels will stay docked, lights on, air-conditioner and ventilation running, and kitchens firing to house thousands of delegates, negotiators, and media for the 30th UN Climate Change Conference (COP30).

Once the summit is over, the ships will revert back to their cruise itineraries and head south to Santos. Their itineraries will resume as follows:

Costa Diadema → Weekly 7-night loops to Buenos Aires and Montevideo.

MSC Seaview → Week-long Northeast Brazil beach runs.

They’ll join an already stacked 2025-26 South America season that includes MSC Preziosa, MSC Fantasia, MSC Sinfonia, MSC Armonia, and Costa Favolosa, plus visits from Oceania, Scenic, Regent Seven Seas, Celebrity, and AIDA. The regional season kicks off late October and runs through mid-April 2026.

Two ships, one ocean crossing, zero emissions from idling hotels on land. This is Brazil’s greenest accommodations for the world’s biggest climate talk.