Ten Top Tips for Tidal Open Water Swimming

Ten Top Tips for Tidal Open Water Swimming

By Tim Wiggins

Open water swimming in tidal waters is an exhilarating and unique experience. The open waves are like no other pool and coastal open water swimming can open up amazing opportunities to explore creeks and hidden coves.

It can also be challenging though and not without potentially dangerous consequences for the unprepared swimmer. Learning about the potential hazards and doing what you can to mitigate them is good practice for open water swimming on tidal coasts.

Drawing on my experience swimming, sailing and kayaking on coasts around the world, these are my Top Ten Tips for safe and enjoyable open water swims on the coast. The first five are tips for pre-swim preparation, while the latter five are advice for when you are in the water.

1. Buy a Tidal Flow Atlas and Tide Timetable  

Tidal flows are the greatest danger with open water swimming in coastal waters. Get it wrong and you could be battling against a tide flow far stronger than your swimming prowess - a force that could sweep you out to sea and place you in very real danger.

To understand the tidal flows in your area, it is necessary to purchase a tidal flow atlas or an App-based equivalent. These maps show you the direction of flow at different stages of the tide. Paired with a tide timetable you can then know the high-water time and check your atlas to know which way the tide will flow at any given hour. Of course, you should always double check this by looking at buoys and moored boats at your swimming location and observing how the water flow is affecting them. 

Understanding the tidal flows is key to knowing which direction to swim in. More on this in Tip 6.

 2. Learn When You Can Swim 

Tidal waters flood and ebb twice a day. At low water, there may not be enough water to swim. You can use your tide tables and ask locals about water depth to work out when you will have enough water to swim.

 3. Be Aware of Tidal Flushes 

If you are swimming close to a harbour, then it is worth considering the fact that the harbour ‘empties’ when the tide is dropping from high tide to low tide. The water emptying from a harbour can bring with it some unpleasant debris and sediment. If you can and it makes sense with the tidal flows, then it is worth swimming in the hours before high water to avoid the tidal flush.

4. Consider A to B Swims and Day Swims

When planning your open water swims in tidal waters, consider the idea of a 'Point-to-Point' swim or a 'Day Swim'. This is a fantastic way of using the tide flows in your favour; you can let the tide carry you down from your starting point to a rendezvous with some friends on a beach, then wait for the tide to turn before heading back. You will feel like you have a helping hand on both legs of the swim!

5. Swim Within Your Limits  

In tidal waters, it is even more important to only plan to swim within your limits. This does not mean you cannot go for PB's and new distance records, but always ensure you leave a little extra in your tank so you can make it back against the tide if you have to.

6. Start Swimming Against the Flow

In cycling, there is a mantra of 'Headwind out. Tailwind home' – the reasoning behind this is that you are assisted by the elements when you are more tired in the second half of your route. The same principle applies to tidal waters – it is best to swim out against the current, then turn around and let it carry you back to your starting point. Using the tidal flow knowledge obtained from your tidal atlas, as well as your observations, you should easily be able to swim against the current on your outward leg.

7. Stay in Shallow Water. Avoid Deep Water Channels

Tidal flows are less in shallow water, so it pays to swim closer to shore. It is also worth noting that deep water channels are used by shipping – making them even more hazardous. Stick to swimming in shallow water to reduce the danger from tide and other water users; a good bet is to try and swim parallel to the shore, just out of your depth.

8. Wear a High-Visibility Swim Cap

Visibility is even more important during open water swims on the coast, as you are likely to be sharing the water with pleasure craft and commercial shipping. A high visibility orange, yellow or neon green swimming cap, such as those from Zone3, are an inexpensive way to help improve your visibility.

9. Use a Safety Float

In addition to a swimming cap, a high-visibility colour safety pull float should be a mandatory accessory for coastal open water swimming; it helps make you more visible to other water users, helps make you more obvious to any potential rescuer, and supplies a potentially life-saving flotation device if you do get into trouble.

10. Have an SOS Device

For even greater protection and peace of mind when open water swimming in tidal coastal waters, consider taking an 'SOS Device' such as a VHF Radio, EPIRB, or a mobile phone in a waterproof case in your safety float. If the tide really catches you out and you feel yourself being taken offshore, this device could be a life-saver.