National Geographic-Lindblad Expeditions is chartering the Greg Mortimer for Alaska cruises starting in 2027.

According to a press release, the SunStone Ships vessel will replace the National Geographic Sea Lion and the National Geographic Sea Bird, which are set to be retired in 2026.

Lindblad stated that the move will expand its operations in Alaska, meeting “strong and growing traveler demand” for the region.

Currently sailing for Aurora Expeditions on a year-round basis, the Greg Mortimer will be chartered on a three-year deal.

The company said that the new ship will enhance its ability to explore more, offer new itineraries and continue building on the pioneering legacy of the National Geographic Sea Bird and National Geographic Sea Lion.

“I am incredibly proud of the exceptional, unique and intimate Alaska experience that our ships and our expert expedition team deliver. Demand for our Alaska voyages continues to grow, and I’m thrilled that with the introduction of a new ship to our Alaska fleet, we can welcome even more explorers and also offer exciting new itineraries to our collection,” said Natalya Leahy, CEO of Lindblad Expeditions.

“We are equally grateful to honor the final farewell season of the Sea Bird and the Sea Lion in 2026. These beloved ships have been the backdrop to countless memorable adventures for our guests over many years. We invite travelers to join us for this special farewell season,” she added.

Lindblad highlighted Greg Mortimer’s features, noting that the 160-guest ship was designed for expedition cruising in remote environments.

“That supports the company’s vision to go farther and design new routes that deepen guests’ connection to Alaska’s wildest corners,” the company continued.

Part of SunStone’s Infinity-class, the Greg Mortimer was built at the China Merchants Heavy Industry in Haimen and entered service in late 2019.

The National Geographic Sea Bird and the National Geographic Sea Lion are part of Lindblad’s American-flagged fleet.

The 62-guest sister ships were built at U.S. shipbuilder Nichols Brothers and originally entered service in 1982.