Swimming

Water Safety Guide for Open Water Swimming

No lanes, no walls, just open water all around you. Open water swimming feels like freedom in its purest form. But out there, cold, current, and fatigue can turn your swim into a risk. This guide shows you what hazards to watch for and what gear you need. With safety tips from those who know open water best: Ocean's Seven swimmers Nathalie Pohl and André Wiersig, and swim coach and sports scientist Holger Lüning.
Nathalie Pohl André Wiersig Holger Lüning RESTUBE
Experts · Swimming
Nathalie Pohl · Extreme Open Water Swimmer & Ocean's Seven Finisher, André Wiersig · Extreme Open Water Swimmer & Ocean's Seven Finisher, Holger Lüning · Sports Scientist and Swimming Coach & RESTUBE · Water Safety Company

300.000

people drown worldwide every year

WHO – World Health Organization (2024): Global status report on drowning prevention.

60%

have have faced a critical situation in the water, even though nearly 8 in 10 consider themselves good swimmers

RESTUBE, Water Safety Study 2026

100m

is already too far to swim for most adults who consider themselves good swimmers

Stanley et al., International Journal of Aquatic Research and Education (2024)

10°C (50 °F)

water forced half of all competent swimmers to stop early

Tipton et al., The Lancet (1999)

Hazards in Detail

When Things Get Critical in Open Water

From sudden currents to cramps and cold shock, the dangers of open water swimming often arise without warning, in lakes as well as at sea. Here's how to recognize hazards early and handle them safely.

  • Cold shock?

    Cold shock?

    Cold water can take your breath away, whether you fall off your board or dive into a lake. In the first moments, your body reacts with gasping and rapid breathing, and you can quickly lose control. Stay calm, lean over your buoy, and give yourself a minute to breathe before you move on.

  • Fading power?

    Fading power?

    Whether you're swimming, paddling, or riding the wind at your back: out on the water, your strength can fade faster than you'd expect – current, distance, or cold all drain your reserves even more. With a RESTUBE buoy, instant buoyancy is always within reach – to catch your breath, or to keep you afloat when it really matters.

  • Panic?

    Panic?

    Falling into cold water, an unexpected wave or losing your bearings can send even experienced water sports enthusiasts into a brief moment of panic. Panic makes you react in a rushed, energy-draining way – the opposite of what you need. Breathe deliberately, lean on your buoy, and wait for your pulse to settle before you act.

  • Got a cramp?

    Got a cramp?

    A cramp can strike without warning, whether you're swimming in open water, training for a triathlon or snorkeling, and often at the worst possible moment. Tired muscles, cold water or dehydration make it more likely. Stop moving, lean over your buoy to take the weight off, and gently stretch the affected muscle until it relaxes.

  • Unexpected current?

    Unexpected current?

    On coastlines, in rivers or tidal waters, a current can pull you away faster than you can swim, even if you're a strong swimmer. Fighting straight against it drains your energy in minutes. Stay calm: at the coast, swim parallel to the shore until the pull eases, then head back. In a river, float on your back with your feet up and pointing downstream and work your way diagonally toward the bank. If you need a break or help, lean on your buoy and use it to make yourself seen.

  • Far from shore?

    Far from shore?

    On the water, distances are deceptively short. Wind, current, or your own enthusiasm can carry you further from shore than you realize. If the way back is suddenly too far, every minute costs you more energy. Signal for help with your bright-colored RESTUBE buoy, and use it to swim back to shore while saving your strength.

  • Rough water conditions?

    Rough water conditions?

    Chop, gusts or swell can quickly turn a relaxed time on the water into a real test of strength. Control and balance get harder, and mishaps pile up. In these conditions, pushing on often isn't safe anymore. Get off the water as soon as you can, and let your buoy help you stand out clearly between the waves.

  • Sudden weather changes?

    Sudden weather changes?

    Weather on the water can change within minutes: dark clouds, rising wind or a storm often give little warning. Out on the water, you feel the effects especially fast. Watch the sky, head in early, and use your buoy so you can be spotted quickly if you need help.

  • Boats and other people in the water?

    Boats and other people in the water?

    From a boat, a jet ski or a board, a person in the water is easy to miss, especially in waves, glare or poor light. Busy lakes, harbours and popular beaches increase the risk of a collision. Stay away from boat lanes, wear bright colours, and use your yellow buoy to mark your position.

  • No buddy?

    No buddy?

    Going out on your own may feel like freedom, but if something goes wrong, no one is there to notice or help. Whether you're swimming, surfing, paddling or fishing, the safest choice is always to head out with a buddy. If you do go alone, tell someone your plan, stay close to the shore and always carry your buoy as a backup.

  • Others in need?

    Others in need?

    Out on the water, you may be the closest person when someone else gets into trouble, whether they're swimming, paddling or have fallen from a boat. Rushing in without support can quickly put you in danger too. Keep a safe distance, pass your buoy to the person in need, and call for help as soon as you can.

  • Had a drink?

    Had a drink?

    Never drink alcohol if you plan to be on the water afterward. It slows your reactions, which can be very dangerous in a real emergency.

Expert Voice

What Our Experts Say

Nathalie Pohl

Nathalie Pohl

Extreme Open Water Swimmer & Ocean's Seven Finisher

Far too many people underestimate how dangerous it can be out there. They think, 'I'm a good swimmer,' but that has nothing to do with it. When a current comes, you can be the best swimmer in the world and you still won't make it. That's why it's so important to think about safety in advance.

READ EXPERT ARTICLE
André Wiersig

André Wiersig

Extreme Open Water Swimmer & Ocean's Seven Finisher

The most important decision often isn't made at the start, but along the way. When wind and waves pick up, or your body signals its limits, stopping isn't failure. Decide beforehand when you'll turn back, and stick to it – even when the goal is already within reach. The sea will still be there tomorrow.

READ EXPERT ARTICLE
Holger Lüning

Holger Lüning

Sports Scientist and Swimming Coach

One really important point in open water is visibility. Make sure you have a swim buoy in a strong signal colour, so others can always spot you. Something can always happen, like a cramp or feeling unwell, especially in open water when you're not used to the waves. Then it's good to be able to stop for a moment, and for someone on shore to see whether you're just taking a break or giving a distress signal.

Open Water Swimming Safety Tips

Before you dive in

Open Water Swimming Safety Tips

Whether you're a beginner or an experienced swimmer, these eight water safety tips prepare you for every open water swim, from a calm lake to wild swimming in the open sea. Built on the experience of open water pros, they help you stay safe and return to shore with confidence.

  1. NEVER swim alone in open water

    No matter how strong a swimmer you are, bring someone along in a kayak, on a SUP or in a boat. If you swim along the coast, at least tell someone on land where you are swimming, which route you plan to take and when you will be back.

    Assisted Rescue: How to Help Safely Without Putting Yourself at Risk
  2. Check the conditions BEFORE every swim

    Find out about currents, tides, wind, water temperature and weather. Even the best swimmers in the world can't beat a strong current.

    Before You Go In: How to Read the Water and Stay Safe
  3. Don't fight against the current

    If you get caught in a strong current, stay calm and save your strength. To escape a rip current pulling you away from the beach, swim sideways, parallel to the shore, until you are out of it.

    Understanding Hydrodynamics: Currents, Surf and Water Movement
  4. Take the cold seriously

    Get your body used to cold water gradually and increase your time in it step by step. If you are shivering heavily, can't think clearly or your fingers go stiff, get out immediately.

    Cold Water, Storms And Visibility: What Every Water Sports Enthusiast Needs To Know
  5. Make sure you can be seen

    Between the waves, a head in the water is barely visible to boats, surfers or rescuers. A bright swim cap and a buoy in a signal colour mean you can be spotted from far away.

  6. Know your limits before you start

    Decide beforehand under which conditions you will stop, for example strong wind, cold or fatigue, and stick to it, even close to your goal. Turning back is not a failure.

    Know Your Limits: Load Management and Physical Warning Signs in Water Sports
  7. Plan breaks and refueling

    Long distances take more energy than you think. With a buoy, you can rest at any time, reorient yourself and lean on it during interval breaks, without rushing or wasting energy. A swim buoy with a drybag also lets you keep a water bottle and energy bars dry.

    Drink, Eat, Swim, Repeat: The Complete Hydration and Nutrition Guide for Swimmers
  8. Stay calm instead of panicking

    Run through possible emergencies such as a cramp, a jellyfish sting or fog in your head beforehand, and you will react more calmly if they happen. If things get tricky, lean on your buoy, breathe calmly and and give yourself time to settle.

    Self-Rescue: How Drown Proofing Can Save Your Life in the Water

In An Emergency

The Drowning Chain of Survival: What To Do in an Emergency

Drowning happens in stages, not all at once – and at every stage, there's still a way to stop it. These are the five links of the Drowning Chain of Survival, condensed for this activity.

The Drowning Chain of Survival: What To Do in an Emergency
  1. 1. Prevent Drowning 1
    1. Prevent Drowning

    Be safe in, on and around water. The most effective link in the chain is the one that stops an emergency from happening in the first place: know the conditions, know your limits, and don't head out alone if you can avoid it.

    Step 1: Prevention Against Drowning: One of the Most Effective Links in the Rescue Chain
  2. 2. Recognize Distress 2
    2. Recognize Distress

    A person in trouble rarely looks like it does in films: little shouting, little waving, often just a quiet struggle at the surface. Knowing the signs means reacting sooner and asking someone to call for help.

    In practice for this activity: As a companion, watch for silent warning signs: head low in the water, a vacant look, no forward progress. Agree on a clear emergency signal with your companion, such as a raised arm or your deployed buoy.

    Step 2: Why Drowning Happens in Silence: Recognizing Distress and Raising the Alarm
  3. 3. Provide Flotation 3
    3. Provide Flotation

    Before anything else, the person needs flotation, their own or from outside, to prevent submersion. Flotation costs no strength and buys time.

    In practice for this activity: When swimming, there's no board to hold on to. Your buoy is your only source of buoyancy, for yourself and for others in need.

    Step 3: Provide Flotation: Why Buoyancy Saves Lives When Drowning
  4. 4. Remove From Water 4
    4. Remove From Water

    Only if it's safe to do so. Getting the person out of the water matters, but not at the cost of a second person in danger.

    Step 4: Assisted Rescue: How to Help Safely Without Putting Yourself at Risk
  5. 5. Provide Care 5
    5. Provide Care

    As needed: call emergency services, check breathing, start CPR if necessary and don't stop until help arrives. What happens on land in the first minutes often decides the outcome.

    In practice for this activity: After swimming in cold water, your body keeps cooling down, known as "afterdrop". Change into dry, warm clothes right away, and don't make your shower too hot afterwards.

    Step 5: Drowning First Aid: ABCDE Assessment, Rescue Breathing, and CPR Done Right
Open Water Swimming Gear for Your Safety

What you need in the water

Open Water Swimming Gear for Your Safety

From your buoy to the right accessories, good equipment won't replace experience, but it keeps you visible, supported and ready to act when every second counts. Here's the essential kit for open water and wild swimming.

  • SAFETY BUOY
    SAFETY BUOY

    SAFETY BUOY

    The Safety Buoy is stored compactly in a belt pouch, so you don't even notice it while paddling. In an emergency, simply pull the trigger and the buoy fills with CO₂ in seconds, giving you instant buoyancy if you fall into the water or need a break. The built-in signal whistle also helps you get noticed if you need help.

    Our Recommendation SAFETY BUOY
  • SWIM BUOY
    SWIM BUOY

    SWIM BUOY

    The Swim Buoy stays permanently inflated and follows you through the water on a leash, whether you're open water swimming, snorkeling or training for a triathlon. It keeps you clearly visible to boats and other water users and gives you something to hold on to whenever you need a break. The RESTUBE Swim Buoy Pro also features a drybag for your keys, phone or snacks, and with the Backpack Straps you can carry it comfortably like a backpack on your way to the water.

    Our Recommendation SWIM BUOY
  • SWIM GOGGLES

    SWIM GOGGLES

    Well-fitting goggles give you a clear view underwater and help you keep your bearings, even when you lift your head to check your direction. In bright sunlight, tinted or mirrored lenses work best, while clear lenses are better for cloudy days or low light. In open water, a wide field of view also makes it easier to keep an eye on landmarks, buoys and other water users.

    Our Recommendation SWIM GOGGLES
  • WETSUIT

    WETSUIT

    A wetsuit, e.g. from Synergy are recommended for water temperatures below 18°C (64°F): it slows down heat loss in the water and, thanks to its closed-cell neoprene structure, also improves your natural buoyancy. The right thickness depends on the water temperature: 2–3 mm up to about 18°C, 4/3 mm between 10 and 18°C, and 5/4 mm or more below 10°C.

Other Equipment & Add Ons for Swimming

Go or No-Go

Self-check

Go or No-Go

Check yourself, check the water, then decide whether to go for an open water swim.

Suitable for

  • Confident swimmers who can manage longer distances in the pool without stopping, starting in calm waters close to the shore
  • Triathletes and endurance athletes who want to train in real-world conditions
  • Experienced open water swimmers, even in light waves or gentle currents, with a companion and a highly visible buoy
  • Cold water and extreme swimmers who have gradually acclimatised to low temperatures over time
  • Children who can swim confidently, only close to the shore, with additional buoyancy and under constant supervision
  • Older people without pre-existing conditions, accompanied and in calm waters

 Better not if

  • You're on your own and no one knows where you're swimming or when you plan to be back
  • Strong currents, surf, high waves, thunderstorms, fog or a sudden change in the weather are expected, and you lack the experience to handle them
  • The water is colder than 15 °C and you're neither gradually acclimatised to the cold nor wearing a wetsuit
  • You're tired, ill or under the influence of alcohol or medication, or have a known heart condition without medical clearance
  • You'd be swimming in areas with boat traffic, in shipping lanes, or at dusk or in the dark
  • The water quality is unknown, questionable or officially restricted, for example due to blue-green algae

FAQ: Open Water Swimming

Curious about open water swimming? Find answers to the most common questions about safety, equipment and swimming in lakes and the sea.

Water Safety Guide

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