Poseidon Expeditions vs Quark Expeditions
Poseidon Expeditions is a small-ship purist — a single 114-passenger vessel, the M/V Sea Spirit, built around maximum time ashore. Quark Expeditions is a polar-only specialist with the widest range of ship sizes in the segment, from classic Ocean-class ships to the helicopter-equipped flagship Ultramarine.
Technical Specifications
| Feature | Poseidon Expeditions | Quark Expeditions |
|---|---|---|
 Ships | M/V Sea Spirit | Ultramarine, Ocean Explorer, Ocean Diamond, Ocean Endeavour, Ocean Nova |
| Passengers | 114 guests | 128–199 guests, depending on ship |
| Founded | 1999 | 1991 |
 IAATO | IAATO member since 2011 | Not sourced |
| Destinations | Antarctica, Arctic (Svalbard, Greenland, Iceland), British Isles | Antarctica and the deep Arctic (polar-only) |
Ships and Fleet
Poseidon Expeditions
A single ship, the ice-strengthened, Rolls-Royce-stabilized M/V Sea Spirit, carrying 114 passengers — small enough that up to 100 guests can go ashore at once under IAATO's limit, with the rest out by Zodiac or kayak, so no one waits aboard.
Quark Expeditions
The widest range of ship sizes of any operator on this site — from the classic Ocean-class ships (Ocean Explorer, Ocean Diamond, Ocean Endeavour, Ocean Nova) up to the helicopter-equipped flagship Ultramarine, carrying 128 to 199 guests depending on the ship.
Destinations and Itineraries
Poseidon Expeditions
Focused on Antarctica (priority season), the Arctic — Svalbard, Greenland, Iceland — and the British Isles.
Quark Expeditions
A polar-only specialist with the deepest Antarctic and Arctic route variety in the segment — no non-polar itineraries.
Price and Value
Poseidon Expeditions is generally positioned as a small-ship purist option with competitive pricing relative to larger fleets. Quark Expeditions spans a range of price points across its fleet, from the classic Ocean-class ships to the helicopter-equipped flagship Ultramarine. Confirm current, itinerary-specific rates directly on each operator's own website.
Onboard Experience
Poseidon Expeditions
Expert expedition team: naturalists, biologists, geologists and historians. Optional sea kayaking, overnight camping in Antarctica, Zodiac cruising and dedicated photography voyages. Up to 3 landings per day, each lasting approximately 2.5 hours.
Up to 3 landings per day, approximately 2.5 hours each.
Quark Expeditions
The widest activity roster in the segment: Zodiac cruising, sea kayaking, stand-up paddleboarding, overnight camping, snowshoeing, hiking, mountaineering, cross-country skiing and the polar plunge, plus (Ultramarine only) helicopter-supported heli-hiking, heli-trekking and flightseeing. Greenland itineraries add "Tundra to Table" Inuit culinary excursions.
Zodiac cruising, kayaking, snowshoeing, and (Ultramarine only) helicopter-supported excursions.
Who Each Line Is Best For
Choose Poseidon Expeditions for the smallest ship on this comparison and maximum time ashore on every landing day. Choose Quark Expeditions for the widest range of ship sizes and the deepest activity roster, including helicopter-supported excursions on its flagship.
Frequently Asked Questions
Is Poseidon Expeditions bigger or smaller than Quark Expeditions?
Poseidon's 114-passenger M/V Sea Spirit is smaller than every ship in Quark's fleet, which ranges from 128 guests on its smaller Ocean-class ships up to 199 guests on its flagship Ultramarine.
Which operator offers more time ashore, Poseidon or Quark?
Poseidon Expeditions markets up to 3 landings a day, each lasting approximately 2.5 hours, as a direct benefit of its small 114-passenger size. Time ashore for Quark's larger ships varies more by vessel and itinerary.
Does Quark Expeditions offer helicopter excursions?
Yes, on its flagship Ultramarine only — heli-hiking, heli-trekking and flightseeing. Poseidon's single ship, the M/V Sea Spirit, doesn't offer helicopter-supported activities.
Does Poseidon Expeditions offer more ship variety than Quark?
No — Poseidon operates a single ship, the M/V Sea Spirit. Quark Expeditions has the widest range of ship sizes of any operator on this site, from Ocean-class ships to the helicopter-equipped Ultramarine.
When was each operator founded?
Poseidon Expeditions was founded in 1999. Quark Expeditions was founded in 1991.