Why a practice session at Serpentine Lido is a training game-changer

If you’re not based in London, you can book an open water induction closer to home by checking out our top spots.

“Always try and practise in the place you’ll be swimming in for an event,” says Marianne Clark, an open water swim coach at Ocean Set in Brighton. “It will help you feel more confident on the day as you’ll be familiar with the setting.”

You won’t be able to swim the actual course - only members of the Serpentine Swimming Club can swim in the main lake outside of the event, during their early morning sessions - but you will be able to swim in the Serpentine Lido, a 100-metre-by-30-metre sectioned-off rectangle of the main lake. The experience of swimming in the lake – in terms of visibility, water colour and movement, temperature, and the wild setting will set you up perfectly for Swim Day.

The Serpentine Lido is an unimaginable oasis of calm in the middle of leafy Hyde Park, a stone’s throw from some of London’s most bustling streets. 

I visited on a midweek morning in early June and was struck by how serene and secluded the setting was. The daily life of Hyde Park – the runners, the horse riders, the tourists on pedalos – was visible yet distant. And when I got in the water the only other people in were a couple of day-trippers from the Wirral, who were swimming gentle lengths in swimwear on the far side, and two triathletes in wetsuits training more vigorously.

Swimming the 100-metre-by-30-metre rectangle would be a great way for first-timers to get a taste of open water swimming in a safe, life-guarded setting and it allowed me to stretch out far more than I would in a swimming pool.

The lack of big, brightly coloured inflatable markers, which you get at swim events, meant that sighting was a challenge, but that was a good thing, as it forced me to really get my head out of the water to check I was swimming in a straight line. A skill that even experienced open water swimmers always need to practise. 

The water was clear and tasteless, and it was slightly surreal to be sharing the space with moorhens and geese, though they seemed completely unfazed by my presence. The day I visited was also windy so there was plenty of resistance in the water, which is always good for building up open water swimming experience and fitness.

The temperature was around 18°C, but the air was a few degrees cooler, which felt fine when I was wearing a wetsuit but fresh when I did a couple of lengths without at the end of the session.

I walked away through Hyde Park feeling invigorated and amazed that this beautiful freshwater lake not only exists but is also open for outdoor swimming in such a prime central London location.

Here's what to expect during your visit.

While the water in the Serpentine is usually clear - except after stormy weather, as with many lakes - the visibility is extremely limited. This can be unnerving for swimmers who are used to training in a pool and is one of the biggest reasons why it’s smart to book a taster swim here before your event. It's also a good time to practise sighting as you’ll be relying on this technique to make sure you’re going in the right direction without the help of lane lines you’d have in a pool.

The average water temperature in the Serpentine ranges from 15°C in May to 20°C in July. In September, the month of Swim Serpentine, it’s usually around 17°C, but recent warm or cold weather can tip it a few degrees in either direction. Swimming in the lake regularly is a great way to acclimatise to open water swimming in cold water. It’s important to also factor in the air temperature, which you’ll definitely notice on cooler days, so make sure you have warm clothes to put on after your swim.

Open water swimming is quite different from swimming in a pool. Unlike pools, open water environments, such as lakes, rivers, and the sea, are exposed to the elements and are not treated with chlorine. This means that factors including rainwater, wildlife, and warm weather can all influence the quality and safety of the water.

When you’re swimming in a natural setting, it’s always good practice to swallow as little water as possible, shower well when you get out and not swim if you have open cuts.

The Serpentine Lido has outdoor cold water showers and mixed changing room facilities. There are also accessible cubicles and parent and child cubicles.

There is ramp access in and out of the water for swimmers with disabilities, and carers can go free of charge.

The Serpentine Lido is open from 10:00 to 18:00 every day from June to mid-September. Sessions are life-guarded, and prices start at £4.30, with locker rental £2. The lido does get busy during hot weather, when it’s best to come earlier in the day to avoid the crowds. You can book your session online via the Royal Parks site.

Written by Sam Haddad. Sam is a freelance journalist based in Brighton, she's been writing about sport and the outdoors for over 20 years. Photography by Michael Leckie.