First of all, there are a few differences between lake and sea swims that you will need to take into account. The first is the salt in the water. This means that you may well be a little more buoyant when swimming (which is often a good thing!), but might also cause a problem if you swallow too much water, and can, with some people, lead to issues with nausea.
While little can be done about feeling nauseous after swallowing water you can try to reduce the amount you swallow by practising the timing of your breathing and being able to switch your breathing side so that you’re able to breathe away from any swell or waves.
How to cope with waves when swimming in the sea
This brings us to the second major difference with sea swimming – the waves. With many sea swims there will be waves or some swell. This often results in a gentle up-and-down rolling motion while swimming. If you’re swimming across the waves this gentle undulation often won’t provide too much of a problem, but there may be some restriction in viewing the turn buoys. As a result you will need to practise timing your sighting so that you do so when at the top of the wave to make sure you get the best view possible.
How to cope with currents when swimming in the sea
The third major difference is the presence of a current. While lakes often don’t have a current you may well have come across currents if you’ve done any river swims. These may go in your favour and carry you faster towards your destination, but they may also move across your swimming line, meaning you have to sight regularly and make constant adjustments to make sure you stay swimming in a straight line.
Practice and familiarisation to these conditions are key to overcoming all of these differences.
Check out our guide to ten UK triathlons with (very) challenging open-water swims here