Expedition cruises focus on visiting some of the most remote and pristine wilderness regions in the world. Their ships are small and range from fairly basic ice-breakers to purpose-built luxury expedition vessels. All have a very casual onboard dress code and all carry onboard destination specialists. These cruise lines tend to receive their ratings based more on the expedition experience than on the actual ship itself.

Lindblad National Geographic Expeditions (6 star): Arctic, Antarctic, Galapagos Islands, Alaska, Amazon, Baja California, Central America, Columbia and Snake Rivers, Egypt, South America, New Zealand.

Quark Expeditions (5 star): Arctic and Antarctic

Orion Expeditions (5 star): Antarctica, Australia, Papua New Guinea, Borneo, China, Japan.

Silversea (5 star): Arctic, Antarctic, West Africa, northern British Isles and Latin America.

Celebrity Cruises(5 star): Galapagos Islands