5 Dangers of Swimming in Open Water (And How to Stay Safe)

As temperatures rise across the UK, more people are looking for ways to cool off. Rivers, lakes, quarries and the sea can seem like an inviting place to swim on a hot day, especially when beaches and swimming pools are busy. However, understanding the dangers of swimming in open water is essential before taking the plunge.

Recent news reports have highlighted several heartbreaking incidents involving children, teenagers and adults getting into difficulty while swimming in open water. While swimming is a fantastic life skill and a great way to stay active, open water presents risks that differ significantly from those in a supervised swimming pool.

Many of the recent incidents reported in the news have involved children and teenagers entering open water to cool off during hot weather, often without fully understanding the potential dangers of swimming in open water. 

In this article, we’ll explore the 5 main dangers of swimming in open water and explain what parents can do to help children and teenagers stay safe around rivers, lakes, quarries and coastal waters this summer. 

1. Cold Water Shock: One of the Biggest Dangers of Swimming in Open Water

Many people assume that if the weather is warm, the water must be too. Unfortunately, that’s often not the case.

One of the most serious dangers of swimming in open water is cold water shock. Even during a heatwave, rivers, lakes and reservoirs can remain surprisingly cold. Entering cold water suddenly can cause an involuntary gasp reflex, rapid breathing and an increased heart rate.

As a parent, it’s important to help children understand that warm weather does not mean warm water. Many young people assume that a river or lake will provide a safe way to cool down, without realising that cold water shock can affect even strong swimmers within seconds. 

This reaction can make it difficult to stay calm and control your breathing, increasing the risk of panic and drowning.

What parents should teach their children :

• Enter the water slowly rather than jumping straight in.
• Give your body time to adjust to the temperature.
• Avoid swimming if you’re overheated after exercise or sunbathing.
• Wear a wetsuit if participating in open water swimming activities.

2. Hidden Currents and Underwater Hazards

Another of the major dangers of swimming in open water is that you can’t always see what’s happening beneath the surface.

Rivers can have strong currents that quickly pull swimmers downstream, or even under the water. An excellent example of this is the seemingly benign Bolton Strid on the River Wharfe in North Yorkshire. While calm in appearance on the surface, incredibly strong underwater currents on this stretch of water are said to have a 100% fatality rate for anyone who tries to swim here. Coastal waters may have powerful tides and rip currents that can carry even strong swimmers away from shore. Lakes and quarries often contain submerged debris, rocks, weeds and other hidden obstacles.

What appears calm on the surface may be much more dangerous underneath.

What parents should discuss with their children :

• Only swim in designated swimming areas where possible.
• Check local safety advice and warning signs.
• Never assume a body of water is safe because others are swimming there.
• Stay clear of areas with strong currents, weirs or fast-flowing water.

3. Sudden Changes in Depth

Sudden drop-offs are among the lesser-known dangers of swimming in open water, but they can catch swimmers off guard.

Unlike swimming pools, where depths are clearly marked, natural bodies of water can change dramatically within a few steps. A shallow area can suddenly become very deep, causing inexperienced swimmers to panic.

This is particularly dangerous for children and teenagers, who may not recognise how quickly shallow water can become deep water. Losing their footing unexpectedly can lead to panic and place them at greater risk. 

Quarries can be especially hazardous because of their steep underwater sides and extreme depths.

How to avoid it:

• Never dive into unknown water.
• Supervise children closely at all times.
• Stay within your swimming ability.
• Wear a buoyancy aid if appropriate.

4. Poor Visibility and Water Quality

Poor visibility is another important factor when considering the dangers of swimming in open water.

In many lakes, rivers and quarries, the water can be murky, making it impossible to see hazards below the surface. Swimmers may become entangled in weeds, encounter submerged objects or struggle to orient themselves underwater.

Water quality can also vary significantly. Some locations may contain harmful bacteria, pollution or agricultural runoff that can cause illness.

How to avoid it:

• Choose recognised swimming locations where water quality is monitored.
• Avoid swimming after heavy rainfall, which can affect water quality.
• Do not swim in waters where swimming is prohibited.
• Check local authority or environmental agency guidance before swimming.

5. Overconfidence and Lack of Water Safety Awareness

Perhaps one of the most preventable dangers of swimming in open water is overconfidence.

Many people who are comfortable swimming in a pool assume that the same skills automatically transfer to open water. However, swimming in a pool is very different from swimming in rivers, lakes, quarries or the sea.

Open water swimmers face changing temperatures, currents, waves, limited visibility and longer distances from safety.

Teenagers are particularly vulnerable, as they may underestimate risks or feel pressured to take chances with friends.

Many recent open water tragedies have involved teenagers spending time with friends during warm weather. Peer pressure, dares, overconfidence and a lack of awareness about cold water shock can lead to risky decisions. What starts as a fun way to cool down can quickly become an emergency. 

What Parents Can Do :

• Talk openly about the dangers of swimming in open water before hot weather arrives.
• Remind children that strong swimmers can still get into difficulty.
• Explain that rivers, lakes, reservoirs and quarries are very different from swimming pools.
• Encourage children to avoid dares or risky behaviour around water.
• Make sure they know never to enter open water alone.
• Encourage them to think carefully before entering any unfamiliar body of water.

What Should Parents Teach Their Children About the Dangers of Swimming in Open Water?

One of the most effective ways to reduce the dangers of swimming in open water is through education and open conversations at home.

Parents should help children understand that:

• Warm air does not mean warm water.
• Strong swimmers can still drown.
• Jumping into unknown water is extremely dangerous.
• Rivers, lakes, reservoirs and quarries are not the same as swimming pools.
• Hidden currents, underwater obstacles and sudden drops in depth can put swimmers at risk.
• They should only swim in safe, supervised locations whenever possible.

Most importantly, encourage children and teenagers to stop and think before entering open water. A simple conversation about the dangers of swimming in open water could help prevent a tragedy.

Understanding the Dangers of Swimming in Open Water Could Save a Life

The dangers of swimming in open water should never be underestimated. While open water can provide an enjoyable way to cool off during hot weather, it’s important to remember that rivers, lakes, quarries and coastal waters are unpredictable environments.

Understanding the dangers of swimming in open water, recognising your own limitations and making informed decisions can significantly reduce the risk of accidents.

If you see someone in trouble in the water, avoid entering the water yourself unless you’re trained to do so. Call 999 immediately and ask for the Coastguard if at the coast, or Fire and Rescue Services for inland waters. If possible, throw something that floats and encourage the person to float on their back while waiting for help.

If You Get Into Trouble in Open Water

If you unexpectedly find yourself struggling in open water, the RNLI recommends remembering one simple message: Float to Live.

The key steps are:

• Tilt your head back with your ears in the water.
• Relax and try to control your breathing.
• Use your hands to help you stay afloat.
• Avoid thrashing or panicking.
• Once your breathing is under control, call for help or swim to safety.

These simple actions can help counter the effects of cold water shock and have helped save lives.

Build Water Confidence and Swimming Skills with Swim-With-Me

At Swim-With-Me, we’re passionate about helping children develop the confidence, technique and water safety skills they need to stay safe around water. We also believe that educating families about the dangers of swimming in open water is an important part of keeping young people safe during the summer months. 

We offer expert swimming lessons in Colchester, swimming lessons in Clacton, swimming lessons in Cheshunt and swimming lessons in Walthamstow, with experienced instructors, small class sizes and a supportive learning environment.

However, swimming ability is only one part of staying safe around water.

Education, awareness and good decision-making are equally important.

As we enjoy the warmer weather this summer, please take a few minutes to have a conversation with your children about the dangers of swimming in open water. It could be a conversation that saves a life.

To find out more about our swimming lessons and book your place, get in touch with the friendly Swim-With-Me team today.