What to Wear Diving and Snorkelling in Cool Water
Cool water is the trickiest category to dress for. It is not cold enough to obviously need a thick wetsuit or a drysuit, but it is cold enough that a rashguard alone will leave you shivering within twenty minutes. Here is a practical way to think about it.
Why "cool" is harder to dress for than "cold"
In genuinely cold water, the decision is easy: you wear a drysuit or a thick wetsuit, no debate. Cool water sits in an awkward middle ground. Go too light and you cut your dive or snorkel short from the cold. Go too heavy and you are overheating on the surface, fighting a stiff wetsuit for no reason, and probably still cold on a windy boat afterwards anyway.
What actually determines what you need
A few things matter more than the water temperature number on its own:
- How long you will be in the water. A twenty-minute snorkel and a sixty-minute dive ask very different things of the same water temperature.
- How many times you will get in. Repeat dives or repeat snorkel sessions in a day mean your body heat is already depleted by the time you get back in.
- What happens between sessions. A windy boat deck or an exposed beach between swims is often colder than the water itself.
- How much you move. Snorkelling near the surface with little exertion generates less body heat than active diving or swimming.
Options for cool water, from light to heavy
Rashguard or swim shirt
Fine for sun protection and short, warm-water sessions. Not enough insulation for cool water beyond a short swim.
Sharkskin thermal wear, worn alone
Chillproof is built for exactly this middle ground: enough warmth for cool water without the bulk of a wetsuit, and it blocks wind on the surface between snorkels or dives, which is where most people actually get cold. It works for snorkelling, diving, swimming and other watersports without switching kit between activities.
Sharkskin as a layer under a thin wetsuit
If cool water tips over into genuinely chilly for you personally, wearing a Sharkskin layer under a thin wetsuit adds warmth without adding much bulk, useful for divers who run cold or who are doing several dives in a day.
A full wetsuit
Still the right call once the water is properly cold, or if you are especially sensitive to cold. It comes with the trade-offs covered in our Sharkskin vs a Neoprene Wetsuit comparison: warm in the water, bulky and cold once you are out of it.
A simple way to decide
| Session | Likely best option |
|---|---|
| Short, warm-leaning snorkel | Rashguard, or Sharkskin Chillproof if the wind is up |
| Longer snorkel or swim in cool water | Sharkskin Chillproof |
| Single dive in cool water | Sharkskin alone, or as a layer under a thin wetsuit |
| Repeat dives through the day | Sharkskin T2 Titanium, alone or layered |
| Genuinely cold water | Full wetsuit or drysuit, with Sharkskin layered underneath |
Do not forget the surface
Whatever you dive or snorkel in, plan for what happens when you get out. A windy boat, an exposed jetty or a breezy beach can make you colder than the water did. A windproof thermal layer for the surface interval is often the single biggest comfort upgrade for cool-water sessions, more than upgrading the suit itself.
A note for groups and families
Cool water trips often mean a mix of confidence and cold tolerance in the same group: one person is happy in a rashguard while another is shivering in a full wetsuit. Thermal layers are useful here because they scale - a nervous or cold-sensitive swimmer can add a Sharkskin layer without needing a whole wetsuit fitted, and everyone can be comfortable without the group having to dress to the coldest person's needs.
Choosing between Sharkskin's ranges
If you already know you want a Sharkskin layer but are unsure whether Chillproof or T2 Titanium fits your conditions, our guide on Chillproof vs T2 Titanium walks through it by conditions and use. For the broader question of how to stay warm across a full day of diving, see how to stay warm scuba diving.
You can see the current range at sharkskineurope.com, and the care and warranty guide covers looking after it. If you are not sure what suits your local water temperature, get in touch - happy to help you pick.