Guide to cold water diving - for scuba divers on polar cruises

When you think of exotic diving destinations, chances are it’s not the ice-choked polar regions that spring to mind. But, experienced scuba divers will be well-aware that cold-water locations can be every bit as exciting as their tropical counterparts. And, the Arctic and Antarctica represent the epitome of cold-water diving. Delivering unique conditions and wildlife, and one-of-a-kind scenery, these isolated frontiers are the ultimate bucket-list destinations for experienced scuba divers.

It goes without saying that diving in the frigid waters of the Arctic and Antarctica is not for the uninitiated. So, to help you understand what’s involved in a polar diving experience, and what’s required from the divers themselves, ZuBlu's travel team have put together an introduction to cold-water diving.

Before we dive any deeper, it’s worth exploring exactly what we mean when we say ‘polar diving’. Simply put, polar diving is scuba diving in the frigid waters of the world’s polar regions - the Arctic and Antarctic. Understandably, ice is often the first thing that comes to mind when people think about these destinations. And yes, the ice shelves and icebergs – along with their unique inhabitants – are one of the main attractions to scuba divers visiting the polar regions. But, there is a significant difference between polar diving and ice diving.

As mentioned above, polar diving refers to scuba diving in and around the Arctic Circle or the Antarctic Circle. These experiences take place in frigid – and at times freezing – water temperatures and involve exploring a variety of environments, including the edges of large ice sheets and the steep walls of icebergs. While this might sound like all the characteristics required for ice diving, this term is actually reserved for the act of scuba diving beneath the ice itself, achieved by entering the water through a hole cut into the ice sheet. With limited means of egress, ice diving is considered to be an overhead environment, requiring additional training and experience.

Polar diving in the Arctic and Antarctica is typically done from zodiacs, which can get close to the rocky shoreline or ice shelf and drop divers onto the slope. Dives can even take place around icebergs, though this poses some additional risks that must be taken into account. For example, the iceberg should either be grounded, or – if it is floating – the surrounding waters should be free from pack ice. Whether it’s an ice shelf or free-floating iceberg, finning along a wall of frozen water is an experience you’ll never forget. And, the interplay between light and ice is utterly mesmerising, creating beautiful hues of blue and green. Freshwater run-off from glaciers and icebergs can also create captivating visual displays as different temperatures and salinities collide.

What many people don’t realise, is that these polar destinations also offer plenty of ice-free dive spots. While the water may still be cold, scuba diving at these sites often focuses on fields of kelp and rocky seabeds covered in algae, anemones, and hydroids. If ice dives are all about the scenery, then these alternative sites are all about marine life, as they offer a wealth of nudibranchs, crabs, shrimps, starfish, amphipods, scallops, lumpsuckers, and more. And, there’s always the chance of encountering larger polar wildlife including seals and penguins.

Of course, one of the more challengin aspects of a polar diving experience is the water temperature, which is frequently below 5°C. And, with -2°C marking the freezing point of saltwater, divers can often find themselves submerged in temperatures below 0°C. While there are numerous health benefits thought to be associated with cold-water immersion, scuba diving in such extreme temperatures can certainly take a toll. As a result, underwater explorers will often find themselves expending more energy, consuming air more quickly, and becoming fatigued easily. Thankfully, having appropriate scuba experience will mitigate many of these issues below the water, allowing divers to stay calm and remain within their limits. Polar expedition cruises also offer far fewer dives than warm-water scuba safaris, allowing long surface intervals for divers to warm themselves up. A common rule of thumb is to spend four times longer on the surface than you did underwater. 

While polar diving is not necessarily technical, it is far more intensive than a typical recreational dive, and a certain level of experience is required. The icy temperatures present plenty of additional challenges, particularly in terms of equipment, mentality, and physical wellbeing. In addition, during a typical polar expedition cruise, the guides stay on the surface while buddy teams dive below. As a result, anybody wishing to try polar diving should have a minimum certification level of advanced open water, or another suitable alternative. They should also be comfortable with the use of dry-suits and be able to evidence numerous logged dives involving the use of dry-suits in cold waters. Of course, this is just the minimum level of knowledge required, with any additional certifications and experience only adding to your safety and enjoyment.

Cold-water or polar diving may not be technical, but it is equipment intensive. Not only do divers require specialised gear to keep warm, but some pieces of standard scuba equipment may not function at such low temperatures. Therefore, it is important to ensure you have the correct items for a polar diving adventure and have tested them rigorously before arriving – the Arctic and Antarctica are not places to be toying with equipment for the very first time.

Testing your gear in advance is crucial, as the extreme conditions can push even the best equipment to its limits. A reliable scuba diving gear shop can guide you in selecting the right drysuit, regulators, and other essentials designed for freezing waters. Regulators, for instance, must be cold-water rated to avoid freezing and malfunction. Additionally, thick neoprene gloves and hoods are necessary to protect extremities from the harsh cold.

Cold-water diving requires you to be well-versed in the use of a dry-suit, as they are the only adequate protection in Arctic and Antarctic waters. Though they offer limited thermal protection on their own, the fact that they provide a water-tight barrier allows divers to wear insulating items underneath. These undergarments are typically made of synthetic materials and include a moisture-wicking base-layer – to avoid sweat cooling the body – and a fleece-like layer for warmth - nicknamed a ‘woolly bear’.

A thick hood with decent face and neck seals is another vital piece of insulation during polar diving, often coming already attached to dry-suits. Different glove options are available to polar divers, depending on your preferences. Neoprene gloves can be used with any dry-suit and offer a choice of styles – five-finger gloves allow for more precise movements, but three-fingered mitts provide more warmth. Or, divers can decide to use dry gloves which seal against the wrists of the dry suit. This type of glove demands additional practice, as they can fall off if used incorrectly and require tubing to be placed under the wrist seals to ensure warmth and prevent squeeze.

Standards regulators can easily freeze if used in the ice-cold waters of the Arctic and Antarctica. Divers must use regulators fitted with environmental sealing, to avoid ingress of water, and must utilise a configuration involving two first and second stages. This way, if a primary regulator freezes and begins to freeflow, the valve can be closed and the back-up regulator used instead. 

To minimise the chance of malfunction, regulators need to be cared for diligently during polar diving expeditions. Before connecting your first stage, always remove any moisture from the orifice by momentarily opening the cylinder valve. Only breathe through the regulator briefly before submersion, to ensure it is functioning, and remove the regulator from your mouth before exhaling to minimise the chance of moisture entering the second stage. Once the dive is complete, hold the second stage lower than the first stage when purging prior to removal, and disconnect the regulator carefully to stop ice and water from falling into the filter. Finally, it is advisable to avoid rinsing regulators between dives.

Of course, the above is a very brief introduction to an activity which requires plenty of prior planning and knowledge. So, if you’d like to read more about cold water scuba diving, we recommend the following articles.

DAN – Five lessons for cold-water diving
DAN – Avoid the chill
Oceanwide Expeditions – Polar diving: a supreme underwater adventure
NAUI – Effects of cold water diving and tips to counteract them
Scuba Diving Magazine – What is takes to scuba dive in Arctic conditions