Polar Diving
Essentials

Polar diving is diving near the poles: north of the Arctic Circle or close to it, or south of the Antarctic Circle. It’s also shorthand for cold-water diving. “Cold” is relative, but in polar diving it generally means water from around 0°C (32°F) up to 3 to 4°C (38 to 40°F).

Salt water can get colder than fresh water before it freezes. In the sea, you may dive water as cold as −2°C (29°F). Fresh water that cold has already turned to ice or slush.

Because what you’ll see is like nothing in the tropics: different marine life, geology and light, and visibility that behaves differently. Above the water, it’s just as different. In places like Greenland, you dive beneath towering mountains, in water that is peaceful and never crowded. It feels special, and you share a bond with your fellow divers that is hard to find anywhere else. Between dives, there’s time to take it all in.

Learning to dive outside tropical and temperate water opens up an entirely new universe of diving. There’s something freeing about that. Greenland, Norway, Antarctica, Iceland, Canada: with the right gear, you can dive almost anywhere in the world.

Four pieces of equipment keep you warm: your drysuit, undergarments, dry gloves and hood.

The Drysuit

A drysuit doesn’t keep you warm. It keeps you dry, keeping water off your skin. Warmth comes from what you wear underneath.

Undergarments

These do the real work. There are two approaches:

Dry Gloves

Like the drysuit, dry gloves keep your hands dry, not warm. They’re silicone or latex gloves that attach to your drysuit with a ring system, so you’ll need a ring system that fits your drysuit. Underneath, wear one or two layers at most: a merino wool or fleece liner. Keep gloves and liners from getting too bulky. You’ll already lose some dexterity, so practice handling your torch and other equipment before the trip.

Feet

Depending on your drysuit, you’ll have attached boots or separate rock boots. Either way, wear a thin wicking sock under a thicker merino or insulated sock, and leave room in the boot.

Moving Warm Air to Your Hands and Feet

That room matters. When your fingertips or toes start to feel cold, add a little gas to your drysuit and let it move into your gloves and boots. The effect is almost instant. It’s one of the simplest ways to regulate your temperature underwater.

The Hood

If you dive a 3 or 5 mm hood, move up to a 7 or 8 mm hood. Thicker hoods exist, but 7 to 8 mm is plenty.

Heated Undergarments

Many cold-water divers use a heated vest or heated undergarment. It isn’t necessary, but it helps on dives longer than about 60 minutes, or if you tend to get cold.

• Use heat toward the end of the dive, generally the last 20 to 30 minutes, so you surface warmer than you started.
• Check your battery before you fly. Airlines limit lithium battery size: spares go in carry-on only, and batteries over 100 Wh need airline approval. Confirm with your carrier.

The key to polar diving is not to rush. Rushing leads to frustration, then anxiety, and to overheating at the surface when the air is warm and you’re in full undergarments. None of that makes for good diving.

Polar expeditions are built for this pace. We usually dive twice a day, sometimes once, with a couple of hours or more in between. Use the time.

People always ask what it feels like when you first get in.

Your body feels fine. The only cold you feel is on your face, the small area between your mask and your hood. The first time, it’s exhilarating. For most people, the sensation fades within seconds, for some a few minutes. Then you’re just diving, focused on everything around you.

More Bulk

Undergarments make you bulkier, so things move. Your inflator, dump valve and D-rings may sit an inch or two from where your hands expect them. After months in tropical water, I’ll reach to clip off my torch and find the D-ring isn’t quite where it was. Expect it, practice it, and don’t get frustrated.

More Weight

Extra undergarments mean more buoyancy, so you’ll need more lead or weight. On a polar dive, that can be 12 to 15 kg (26 to 33 lb) with a 12-liter steel cylinder and a 2.7 kg (6 lb) steel backplate.

Don’t fret. Most of it usually goes on a weight belt, though you can distribute it elsewhere if you prefer. With a drysuit and full undergarments, a weight belt stays secure and is far less noticeable underwater than you’d think.

A standard wing or BCD with 14 to 16 kg (30 to 35 lb) of lift is generally enough for polar diving.

You can dive almost any configuration you’d dive elsewhere. On our 2027 expeditions, there are three options:

• Single-cylinder backmount. We use long 12-liter steel cylinders. Their weight sits in the right place for good trim. Each has a dual-outlet H-valve with two independent first and second stages, so it looks much like a twinset with one gas supply.
• Twinset (doubles). About half our divers choose this. Same 12-liter cylinders, with isolator manifolds and bands provided. Just bring the correct wing. You get redundant gas as well as redundant regulators, so you can handle a gas failure for yourself or a teammate.
• Sidemount. Fewer divers choose it, but we can accommodate it.

A Note on Your BC

Many divers dive a backplate and wing, some a back-inflate BCD, and some a traditional jacket BCD. All of them work, as long as your hoses are routed properly for the configuration.

If your jacket BCD has an integrated inflator and alternate second stage, such as the Scubapro AIR2 or the Atomic SS1, we strongly recommend replacing it with a standard inflator and a separate second stage. Integrated units aren’t suited to gas sharing in polar environments.

If you have questions about your setup, don’t worry. Call us and we’ll talk it through.

Why Redundancy?

Polar diving isn’t technically demanding. But in a remote place, in cold water, with less dexterity and unfamiliar muscle memory, a small problem can escalate faster. Two independent breathing systems are a sensible margin.

In summer, from June through October in Greenland, frozen or free-flowing regulators aren’t a major concern, because the air is warm even though the water is cold. In winter, when the air is cold too, regulator freezing becomes a real risk.

Use environmentally sealed regulators rated for cold water. Most modern regulators are. If you’re not sure yours are rated to 0°C (32°F), ask the manufacturer.

Service everything before you go. Have your regulators cleaned and serviced, along with any equipment that hasn’t been professionally checked recently. Then dive it once or twice before you pack it, if you’re able. Once the ship sails, you want to make sure your equipment will function well throughout the expedition. If you have old hoses, this is a good time to replace them.

Every dive follows set protocols: team diving, light signals, iceberg procedures and pre-dive checks. Our iceberg protocols are covered in detail in Volume 3, How to Safely Dive an Iceberg.

We also encourage limiting alcohol throughout the expedition, even after the day’s last dive. Staying hydrated and clear-headed keeps you ready for the next day’s diving.

To dive polar water, you don’t need technical skills or extensive training. You need the right equipment, familiarity with it and confidence in the water. If you’re learning with an instructor, they’ll judge when you’re ready.

For our Greenland expeditions, the minimum requirements are:

• Advanced Open Water or equivalent, and 150 logged dives
• At least 20 drysuit dives, comfortable with buoyancy and trim in polar undergarments with additional weight
• Prior diving in water at 9°C (48°F) or below
• Your own drysuit and cold-water equipment, and proficiency with them

Polar diving can be comfortable, safe and deeply rewarding when you recognize the environment is different from what you’re used to. Even a few degrees can change how you dive and what you wear, so be familiar and confident with your gear before you go.

Dress for it, prepare for it, and an entirely new world of diving opens up.