Cold Water Diving Guide

For many, the term cold water diving conjures images of wetsuit-clad divers emerging from icy waters, but the truth is, any dive that is in waters with temperatures below 60 °F (15.5 °C) is considered cold water diving.

In this guide, I’ll explore what cold water diving is and give you tips on how to prepare for it and stay safe. Let’s take a deep dive into this mysterious, adventurous world!

What is Considered Cold Water Diving?

Cold water diving is invigorating, and not only due to the temperature! Cold water diving allows you to enjoy the activity you love year-round, no matter what temperature it is. It allows for diving in the winter months too, where you’ll be able to observe the subtle changes in the underwater landscape from one season to another.

Another wonderful advantage is that it opens up many new diving sites around the world. From the arctic waters around Greenland to the frozen murky depths of Scotland’s great Lochs to the freezing seas in Patagonia, diving in cold waters allows you to discover the ‘edge of the world’ and beyond.

There are many different definitions for what ‘is’ cold water diving, however, generally speaking, the most accepted criteria is any dive that is in waters with a temperature below 60 °F (15.5 °C).

Many divers will argue that it’s not only the temperature of the water that defines a cold water dive. It requires specialist equipment considerations too, and this is definitely something most divers will need to plan before dipping a toe into the icy waters they intend to dive.

Diving in freezing water also takes considerable training and requires a strong understanding of diving at mild temperatures. Experienced divers always advise trainee or novice divers to gradually work up to cold water diving.

For a beginner to dive into freezing waters can have negative effects on their health when they are not prepared and properly acclimated. It requires more planning and consideration than a normal dive in mild water temperatures.

How to Prepare for Cold Water Diving

There are a number of considerations divers must take before transitioning from normal to cold water. First and foremost, preparation for the dive is essential. It requires more attention of the underwater environment, to the equipment you plan to use, and the amount of air that you will use should also be carefully checked and double-checked (you use more air at lower water temperatures).

You’ll also need to consider the outdoor environment you plan to stay in between dives. Is there appropriate shelter to stay warm? Will you need to change between dives? Is there anywhere to obtain some warm water to help keep your wetsuit warm?

Exposure protection

One of the most important factors when it comes to being prepared for cold water diving is exposure protection. Many experienced divers will agree that you can never be warm enough and you should always use equipment that will provide the best barrier between the icy waters and themselves.

It’s worth considering that water extracts warmth from the body 20 times faster than air, so if you can avoid contact with the water, it may be wise to do so in more adverse cold water climates.

Wetsuits come in all sizes and thicknesses and the thicker the suit, the more difficult it will be to move freely. Thicker wetsuits can also tire you out faster, as you will have more resistance while moving underwater.

For cold water diving, you’ll likely need a full-body 7mm thick neoprene wetsuit, and in other conditions, a full dry suit may be more beneficial. You will also need something to keep the extremities warm, so consider wearing a wetsuit with a hood, or a separate hood, gloves, and booties.

Drysuits are great as they keep you completely dry which means you will stay warmer between dives. Divers should research the water conditions before they visit the dive site. Be prepared and never skimp on warmth!

Other equipment to consider

The thicker the wetsuit, the more buoyant you will be when trying to submerge underwater, so a steel tank is a good way to add some weight to your kit without overloading your weight belt. Steel tanks are typically 5-8 pounds (2-4 kilograms) heavier than normal aluminum tanks and are considered negatively buoyant no matter if they are full or empty.

With the extra few pounds offered by a steel tank, you may still find yourself being too buoyant, especially if you’re using a thick neoprene wetsuit. Make sure to calculate your weight and it’s very likely you’ll need to add a few more pounds to your weight belt to counter buoyancy.

Check your regulator

Your regulator also needs to be suitable for cold water. Compressed air that flows through a normal regulator at freezing water temperatures can freeze up and cause the air to start free-flowing. While most high-specification regulators will be designed for and work well in cold water, it is important to always check your regulator before embarking on a chilly water dive.

Surface air consumption rates will likely increase in cold water conditions, and this is most commonly due to inexperienced divers being anxious and consuming more air. Divers should also practice and understand how to handle a free-flowing regulator and share masks in the case of a regulator malfunctioning.

Call it when a dive feels too cold

Knowing what your body can and can’t handle is important for any dive, but this is even more paramount when doing a cold water dive. Never jump straight into freezing water as it can cause shock.

Acclimatization is important and it’s worthwhile walking from shore to slowly let your body adjust to the cold water (or getting in slowly from your start point). If using a wetsuit, it takes your body some time to warm up in the water.

Also, if you start feeling too cold, be prepared to abandon the dive early to seek warmer conditions above the water.

Outdoor environment and shelter

Many inexperienced divers focus too wholeheartedly on the dive itself and rarely consider the outdoor environment they must endure between dives.

While waiting between dives, you should also consider what you will be using to stay warm. A thermos with some warm water will help and can be used to warm up the water between your wetsuit and your skin before and after dives. Whenever you remove your wetsuit hood, always make sure you have a warm hat or beanie to retain warmth.

Tips for Diving in Cold Water

cold water scuba diving

  • Ensure you have adequate exposure protection. Never dive with inadequate wetsuits or a poorly fitting suit as this will cause you to become cold quickly, putting yourself at risk of hypothermia and shock.
  • Stay warm before and after a dive. Never start off a dive cold. Take careful consideration of the ambient temperatures before and after your dive to stay warm. Use a thermal hat or beanie to keep your head warm as soon as you exit the water.
  • Before you enter the water, pour some warm water slowly into your wetsuit. This will allow your body to warm the water faster and reduce the risk of you being exposed to cold conditions once you begin the dive.
  • Use a steel tank. Steel tanks are considerably heavier than normal tanks and will reduce the amount of weight you need to add to your weight belt to fight buoyancy. Steel tanks are considered negatively buoyant no matter if they are full or empty.
  • After a dive, warm up with a warm drink and make sure that you have enough clothes to change into (and somewhere to change into them that is out of the elements).
  • Reduce bottom time. Cold water diving is far more fatiguing than diving in warm water and there’s little point trying to tough it out while you are freezing. If you start feeling cold, make your ascent and shave off a few uncomfortable minutes. Hot cocoa anyone?

Also Read: Ice Diving Tips

What is the Difference Between Warm Water and Cold Water Diving?

Besides the obvious temperature difference in the water, there are some other big differences between cold water and warm water diving.

The three most important differences are:

  1. Equipment used
  2. Skill level
  3. Underwater environment

1. Equipment used

You’ll need specialised equipment that will cater to more extreme temperatures. First, you need to cater for adequate exposure protection, within the water and out of the water between dives.

Make sure the type of exposure protection is more than adequate to keep you warm. This will depend on the water temperature so make sure you do your research beforehand. I’ll cover what type of gear you need in the next section.

2. Skill level

More planning and preparation is required, there are simply more factors to consider for a cold water dive.

Dives must be prepared to deal with the extreme water temperatures. The more harsh environment can cause equipment to fail, and divers must be experienced with and have practiced safety procedures when equipment fails or doesn’t work as intended.

Divers need to consider how aggressively cold water fatigues the body. The colder you go, the more important it is for divers to pay particular attention to their body and accurately read their equipment. Divers also understand how much harder it is to swim with additional buoyancy and weight from the drysuit or thick neoprene wetsuits.

Divers must also take into consideration that they will use more air compared to a normal warm water dive. They must be well versed in maintaining breathing at a steady rate. Divers must fight off the anxiety of the sensation of the cold and maintain rhythmical breathing.

Finally, leaving the water, divers must know how to regulate their body temperature and stay warm between dives. They understand the difference between ‘feeling’ cold and the beginning of hypothermia.

3. Underwater environment

With over 6,000 registered PADI sites around the world, there are a substantial number that are set within cold water environments. These sites are generally less crowded by ‘tourist and holiday divers’ and often host a bounty of stunning underwater sights and marine life.

The underwater environment transforms in cold water, and presents a wealth of new marine life to discover and explore. Cold water scuba diving opens the doors to explore shipwrecks, ancient volcanic fissures and walls covered in coral, stunning kelp forests, and lots of marine life that’s not seen at warm water dive locations.

Water visibility is also a huge consideration. Some locations such as Scotland, Norway, Russia, and Iceland are so renowned for excellent water visibility, it’s hard to believe you’re actually underwater.

While water visibility varies at every site and is dependent on other conditions, there are a significant number of great cold water locations that offer incredibly clear water visibility.

Cold Water Diving Gear

Here are some gear recommendations for wetsuit thicknesses and other exposure protection equipment worth considering for cold water.

  • Water temp at 60 °F (15.5 °C): a 3mm neoprene wetsuit is recommended
  • Water temp at 54 °F (12 °C): a 4mm neoprene wetsuit is recommended
  • Water temp at 48 °F (9 °C): use a 5mm wetsuit and consider using gloves and booties to keep your hands and feet warm for prolonged dives.
  • Water temp at 43 °F (6 °C): A 6mm thick neoprene wetsuit is recommended along with gloves, booties, and a hood.
  • Water temp at or below 32°F (0 °C): Use a 7mm neoprene wetsuit with an integrated hood. Gloves and booties are also required. A drysuit would also be a good option at this water temperature, especially when exposed to the water for prolonged lengths of time.

Final Thoughts

While just the thought of diving in cold water may send a shiver down your spine, it is a thrilling and exciting way to explore underwater environments.

Cold water diving is something that is incredibly attractive for divers and what most divers strive for. It is for those who are looking to explore the wealth of incredible dive sites around the world.

Gaining experience and mastering cold water diving unlocks a treasure trove of impressive dive locations that can be explored, and with the right equipment, you will hardly notice the sub-zero temperatures.