How to swim a marathon (in 12 weeks): Preparation and motivation

How do you prepare for a long-distance swim challenge? Gear editor Jo Tinsley takes on the WaterAid Swim Marathon – swimming 26 miles (42.2km) in 12 weeks – in the run up to the official event this summer.

Over the next 12 weeks I’m taking on the WaterAid Swim Marathon – swimming 26 miles (42.2km) in 12 weeks – to document the experience and encourage more people to sign up for this fantastic event happening later in the year. In this first part of my Swim Marathon diary, I’ll be talking about preparation and motivation. But first, what exactly is the WaterAid Swim Marathon?

What is the WaterAid Swim Marathon?

Each year, WaterAid’s Swim Marathon invites participants to swim either a half (13 miles) or full marathon distance (26 miles) over 12 weeks. This year’s event is taking place 1 August 2024 – 24 October 2024 and you can register your interest for the 2024 event. During the 12 weeks, you can swim whenever and wherever you like. In previous years, participants have swum in lidos, the sea and indoor pools

In 2022, 292 people took part in the challenge, swimming a combined total of 2,880 miles and raising just over £25,000 for WaterAid. This is a chance to raise money for the 1 in 10 people who don’t have clean water close to home. With clean water, decent toilets and good hygiene, children are born healthier. They get the chance to go to school and grow up to become adults. Women and men get to earn a living. Whole communities start to thrive. It sounds normal and it should be.

The appeal of a long-distance swimming challenge

I was really drawn to this challenge. I love swimming, but with a writing career and a three-year-old to look after, carving out time to swim regularly can be a real struggle. I need a really clear motivation to prioritise the time. Since I took on the Gear Editor role in November last year, it’s been easier – I’ve currently got 12 goggles to test so technically I can now class my time in the pool as ‘work’! But even so, without a strong personal motivation, it’s all too easy for my swim time to get swallowed up by a pressing deadline, childcare or life admin. 

I’ve been wanting to get fit and increase both the frequency and distance of my swims for a long while now, and this is a great challenge to help me do that. I find the idea of setting an intention and then recording my progress really motivating. I’m also drawn to the flexibility of the WaterAid Swim Marathon; I can choose where and when I swim, and how fast on any given day. It allows space for off days but equally, I need to keep up with regular swims so I don’t fall behind on my 12-week target.

The early morning swim sessions have begun!

Where to swim

While this year’s official WaterAid Swim Marathon takes place 1 August 2024 – 24 October 2024, when open water temperatures will be lovely and warm, I’m starting my challenge in March when it’s harder to swim any real distance in open water, so I’ll be putting in time at the pool for the first part. My local pool is 25m so this breaks down at just over 140 lengths or 3.5km per week. 

As the weather warms up, I’ll start to do more outdoors – at my regular swimming lake, Vobster Quay which has a 550m and 750m course, plus all the many Somerset lidos that start to open in May. I feel like that will be a really motivating factor when just over half way through the challenge, the lido within walking distance of my house opens its doors – 1,688 lengths in the same indoor pool might seem rather daunting otherwise! 

I’m also keen to use the WaterAid Swim Marathon as an incentive to explore new open water destinations. I’ve already got my sights on the glorious art deco Greenbank Pool, Weston Marine Lake, Clevedon Marine Lake and Cleveland Pools in Bath when it re-opens after sadly suffering more flood damage.  

Eyes on the prize! As the water warms up, Jo is looking forward to swimming more in her local lidos and open water venues.

How to prepare yourself to swim a marathon

I chose the 26-mile (42.2km) distance as I wanted to really challenge myself. I’m not that into the idea of joining a mass participation event or setting my sights on a single long-distance swim and having to perform on the day, but I love the idea of chipping away at a longer term goal like this.

I began preparing in January by gradually increasing my distances from 30 lengths (a mix of front crawl and breaststroke) to 40-50 lengths. It didn’t take long to notice the difference in my fitness – I’m now swimming 40 lengths front crawl fairly comfortably. I’ve also noticed that I start to find my flow around the 30-length mark. This is the point where my stroke feels less laboured, my body feels looser and my mind quietens; it’s a great feeling. 

How to break down the marathon distance

There are two main ways you can break a 42.2km swim into manageable swims over several weeks. The first option, if you’re already swimming regularly, is to set a weekly target of the same distance each week and each session and space the distance out evenly. The second option is to build up your distances as your fitness improves. You can see charts of how this might look in our ‘How to plan your Swim Marathon Challenge’ guide.

I’ve opted to build up my distances. It’s less about needing to increase my fitness over time – in all honesty, at the moment I’m still struggling to get to the pool in time to get a full hour in! So for now, I’m aiming to swim 1km (40 lengths) three to four times a week. As the weather warms up and I get to swim outdoors more, I’m aiming to complete a weekly 750m course at my local swimming lake plus two 55-length swims at the lido. 

Thank you for following my journey. I’m 80 lengths down, only 1,608 to go! 

Register your interest for the 2024 WaterAid Swim Marathon.

Follow Jo’s journey to swimming 26 miles (42.2km) in 12 weeks, plus training tips and insights on The Dip, your weekly free newsletter from Outdoor Swimmer. You can find Jo’s fundraising page here.

For more motivation, read ‘Tales from the WaterAid Swim Marathon’, an interview with two swimmers who took part in the event in 2022.

Jo is the Gear Editor for Outdoor Swimmer and also writes news and features for the website. A keen open water swimmer and long-distance walker, she loves seeking out lakes and lidos close to her home in the Mendip Hills, Somerset. She is the author of The Slow Traveller, editor and founder of independent magazine, Ernest, and has previously tested outdoor clothing and kit for BBC Countryfile Magazine, BBC Focus and Ernest Journal.