Full-day scenic cruising · UNESCO World Heritage Site

Some stops on this cruise you walk through. This one you witness. Glacier Bay is a 3.3-million-acre national park and preserve in southeast Alaska, reachable only by air or water — there are no roads in, no crowds at a gate, no parking lot. Just a deep fjord system carved by ice, ringed by mountains, and quiet in a way that's hard to describe until you're sitting in it.

Two and a half centuries ago, there was no bay here at all. When explorers first charted this coast in the 1790s, the whole thing was a solid wall of ice. Since then the glaciers have pulled back roughly 65 miles — one of the fastest glacial retreats ever documented — and what they left behind is the fjord your ship will spend the day exploring. You are, quite literally, sailing through the space the ice used to fill.

Access here is a privilege, not a given. To protect the park, the National Park Service permits only two large cruise ships into Glacier Bay per day, and Princess is one of the select few lines that hold a permit — a nod to its decades-long history with the park. That limit is the whole point: no jockeying for position, no flotilla of boats. Most of the day, it's just your ship and the ice.

Early that morning, as you enter the bay, National PaFull Itineraryrk Service rangers come aboard directly from a small boat. They stay with you the entire day —narrating over the ship's system, giving talks, staffing a station on board, and pointing out wildlife and landmarks you'd otherwise sail right past. From the mouth of the bay, the ship works its way roughly 60 miles up the West Arm to the showpiece: Margerie Glacier, an active, mile-wide river of ice with a face that rises some 250 feet straight out of the water — and that's just the part you can see above the surface. Beside it sits the darker, debris-streaked Grand Pacific Glacier, the one that carved this whole bay.

Here's the part that surprises people: the captain noses the ship in remarkably close to Margerie's face, then holds position and slowly rotates the whole ship, so that every balcony and both sides of every deck get the same front-row view. You don't have to fight for a spot. The view comes to you. Ships typically spend nine to ten hours inside the park, so there's no rushing it.

This is the moment. You'll be standing at the rail, watching a wall of ancient blue ice, and a piece of it — sometimes the size of a car, sometimes the size of a building — will break free and drop into the sea.

And you'll see it before you hear it. Light travels faster than sound, so the ice is already hitting the water by the time the crack reaches you: a deep, splitting boom that rolls off the mountains. The Tlingit, whose ancestral homeland this is, call it "white thunder," and once you've heard it you'll understand why. The bay goes quiet, hundreds of people go still, and then it happens again somewhere else and everyone turns at once.

The water around you tells the story too — bobbing icebergs, harbor seals hauled out on floating slabs of ice, the occasional spout of a humpback. This is a living, moving, cracking landscape, and no two days in it are the same. It's the kind of thing people book an entire trip around, and it's built right into your week.