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Swimming safely in the sea

Qualified swimming coach Sarah Wiseman gives an insight into how to remain safe when swimming in the sea.

Open water swimming is intensely rewarding but comes with obvious risks.

Sea swimming is at the riskier end of the scale due to the ever-changing conditions. A location you may consider ‘safe’ to swim one day may not be the next.

As an open water swimmer, you are responsible for your own safety. Gathering information on potential risks and hazards is a gradual process – you can do this both prior to and upon arrival at your location.

Ask yourself, is it safe for me to swim? Do your own risk assessment of the area you are choosing to swim.

Useful information to help you choose a good swimming spot

Before you go

  1. Aim to swim at a beach that is lifeguarded. If you have never been to the location, speak to the lifeguards – let them know of your plans and, most importantly, take their advice! (Be aware that they are there to manage the main swimming and surfing areas).
  2. Have a look at where other people are swimming. Ask the locals, see if there is a local swimming group (formal or informal – many have social media pages or groups). Aim to go with other people.
  3. Check the weather forecast and tide timetables. Take note of wave and swell height, tide timings and whether it is a neap or spring tide. (Make sure the information is local to the area you are going to!) There a numerous surf forecasting websites that offer tide and wave height predications alongside the Met Office app and website.

Upon arrival   

  1. Take a while to observe the water. Look at what is happening, how is the sea behaving?
  2. What type of waves are they? How are the waves breaking?
  3. What type of beach is it? (Sandy, shingles, pebbles, rocky, silty or muddy)
  4. Are there any rocks? If so, where are they? How big are they?
  5. Are you in a bay or long shore line? Is the bay sheltered?
  6. Can you see any rip currents? Do you know how to spot a rip current?
  7. What is the tide doing? Is the ground wet on a dry day?
  8. Is there anybody else using the beach? Are there any boat users or creel pots in the water? Are the boats motorised or with sails?

Entry and exit points

  1. Plan your exit before you get into the water. Consider any currents, the tidal flow and wind direction. Decide how long you are going to be in the sea for.
  2. Walk from your exit point up to where you would like to start from. This enables you to take a good view and identify any hazards of the stretch of sea you would like to swim.
  3. A good choice for an entry or exit would be an area that you can get out of quickly if needed. Preferably with less pebbles, seaweed or rocks.


Swimming in the sea

Tides – the alternate rising and falling of the sea

Flooding tide

The rising of the sea is known as a flooding tide (tide coming in). High tide is when the tide is fully in. A flooding tide can cut you off, especially if there are cliffs, headlands, rocky outcrops or sandbanks. It can also knock you off your feet. A flooding tide, or high tide, can cover up potential hazards that are usually visible at low tide. Changes in the flow of water can cause rip currents to happen.

Ebbing tide

The falling of the sea is known as an ebbing tide (tide going out). When the tide if fully out, this is known as low tide. Ebbing tides will reveal potential hazards such as rocks, sandbars, seaweed etc. Again, the change in flow of the water can cause rip currents to happen.

Spring tides (full moon, new moon)

On spring tides, high tides are higher and low tides are lower. In other words, spring tides are the biggest difference in water heights and have stronger currents.  They occur every two weeks.

Neap tide (first and third quarter moon)

On neap tides, high tides are lower and low tides are higher than they are on a spring, meaning less water moving. Occurring every two weeks.

The actual heights and intervals of tides vary depending on location. Some locations have two high tides and two low tides, or mixed tides (where two tides meet from different directions). This is why it is important to know the tides of the area you are going to. Having this information will aid you in making a more informed choice for a swimming spot!

Slack tides

The hour before and after a high or low tide is known as ‘slack’ tide, this generally means there is less water moving and weaker currents, however in some locations rip currents will be at their strongest.  Swimming will usually be easier on a ‘slack’ tide (but not always).  An ebbing tide will make it harder to swim back to shore.  The middle two hours of an ebbing or flooding tide is when the most water moves, meaning stronger currents.

Waves – what are they?

Waves are formed by the wind. The size of the wave depends on how long and how hard the wind blows. Waves break as they move into shallower waters closer to the shoreline. How waves break on the shoreline depend on the shape and slope of the ground below it.

The three types of waves

Spilling waves

Usually found on gentle sloping or flat beaches. They happen when the crest (top) of the wave tumbles down the face (front) of the wave. These waves are good for swimmers.

Plunging or dumping waves

Happen on steep, sloping beaches. They break suddenly and with great power, which make these dangerous. The crest of the wave moves forward faster than the base of the wave. It curls over and crashes violently down. The force can knock you off your feet.

Surging waves

These happen on very steep beaches or around rocky areas. A surging wave may never break as it approaches. They can have strong backwashes or undertows which can carry you off into the sea.

What are rip currents?

Rip currents are usually formed when there is a build-up of water on the beach from the tide and waves. They tend to flow from the shoreline back out to sea. They can take you far out to sea and fast. Rips can also form where estuaries run into the sea.

There are three parts to a rip current.

The feeder current

Build-up water flows along the shoreline until it finds the easiest path back out to sea.

The neck

Easiest path for the water to flow back out to sea, could be formed by the shape of the seabed.  The current is at its strongest here.

The head

Where the build-up water from the shoreline disperses back into the sea.

How to identify a rip:

  1. Debris on the surface of the sea, floating away from the shoreline.
  2. Sand, seaweed or other items from the seabed churning.
  3. Lack of waves or breaking waves. Waves may break on either side of the channel. You may not be able to see any waves in the rip current at all.

Rip currents are not ‘fixed’ in place. A rip may change position from one hour to the next. A flash rip is caused by a sudden build-up of water on the shoreline. These happen quickly and can catch swimmers off guard.

How to escape a rip

  1. Stay calm and conserve your energy. Don’t fight with the current.
  2. Think clearly. Try and swim adjacent to the shoreline.
  3. Once out of the rip current, swim directly towards the shoreline.
  4. If you can not swim out of the rip current, calmly float or tread water.
  5. If you are struggling, remember to keep calm, face the shore and signal for help by raising one arm.


Sarah Wiseman - open water coach

Sarah’s top tips!

  • Stay safe. Tell others where you are going!
  • Where possible, swim with others.
  • Where a brightly coloured swimming hat.
  • Use a tow float if you have one.
  • Make sure you have plenty of warm clothing, even in the summer months.

Safer Seas Service app

Swim England recognise it can be difficult to assess the quality of water when swimming outdoors.

The Safer Seas Service app helps you look at the quality of your favourite swimming spots quickly and with up to date information.

The smartphone app helps beach users, sea swimmers and water sports enthusiasts to track pollution events and real-time water quality information.