• Mark Durnford

Preparing for open water swimming

Updated: Mar 30, 2020

How to prepare for open water swimming triathlon

Regardless of how accomplished a swimmer you may be, you never quite forget how it felt when you were about to begin the swim leg of your first triathlon. Understandably the anxiety can be heightened somewhat further if the swim happened to be in open water involving a group start. So whether it really is the first triathlon swim or not, hopefully the following points can help to further prepare you both physically and mentally for the event.

Avoid plodding up and down relentlessly in the pool without using a proper structure to your sessions and an overall training approach to the swim up and coming swim event. I'm afraid it does boil down to the old adage - fail to prepare and you're preparing to fail. Following the example structured training sessions previously given will give you greater awareness of your pacing and the intensity you'll be able to sustain over different swim distances.


It's very likely to be a bit chilly or at least colder than a pool. Using a wetsuit will help but acclimatisation should very much be part of your training. Begin reducing the temperature of your showers during the weeks running up to the event, take cooler baths and aim to mentally manage your breathing rate when getting in. Temperature of water is as much to do with the mind as it is also to do with the physiological effects it can have on us.

Choosing your wetsuit, goggles and hat

You're likely to have to wear a wetsuit for most open water events so take the time to get properly measured and fitted with the correct suit. Choose one that is specifically made for swimming (and not surfing, scuba diving etc). Mobility around the shoulders and neoprene thickness will be the two main differences between these suits.

Aim to secure an agreement with the shop / supplier requesting that you wish to try it out first and check their exchange policy should it not be a comfortable fit. Better still, ask if they offer trial days as many suppliers will regularly run suit trial days where you can ‘try before you buy’ using nearby pool facilities. Even if the first suit you trial fits and feels great, always go through the same process with others so you can make an overall objective decision. You may feel a bit silly in the pool with a wetsuit on but I would imagine you wouldn't dream of running a marathon with a brand new pair of trainers having never worn them prior to the day, so practising with a wetsuit should be no exception to this general rule either. During practise you may notice the suit rubs / chafes around the neck and / or shoulders. Most wetsuit manufacturers design around this problem very well these days but nevertheless it can sometimes be unavoidable, or in the case of swimming in the sea, the salt in the water can cause greater abrasion. To avoid this you could wear a thin rash vest underneath your suit (which will also provide another layer of insulation should you require it), or you could spread a thin film of Vaseline around the neck seal and armpits. Make sure you wipe your hands well before handling your goggles! Consider that when wearing a wetsuit you are still required to go through the process of an initial chill of water entering the suit before you'll begin to feel warmer. It's this water that becomes trapped between your body and the neoprene of the wetsuit that warms from your body heat to create the insulation effect.

Time to choose your goggles wisely. Let’s face it, leaking goggles are never a pleasant experience but even more so when swimming in open water. Having to stop will ruin your rhythm and could knock you off your pacing. Some swimmers choose to use goggles with larger lenses to give them a greater peripheral vision. It boils down to a matter of preference but one point to remember is the tint on your goggle's lenses. If swimming on a overcast, dull day in dark, poor water visibility I'd recommend to use clear or bright yellow lenses to brighten everything up. Equally if you're lucky enough to be swimming on a sunny day in clear water, you'd be wise to use darkened, tinted lenses. Do consider that as much underwater visibility as possible is also of benefit and dark tinted goggles may not be so effective underwater in dark, murky waters regardless of the weather.

With wetsuit and goggles at the ready, we should consider a swim cap. Many open water events will provide you with a swim cap, normally very bright in colour for safety and often with your competition number written onto it. Other than safety, swimming caps provide additional insulation in colder, open water which will in turn also support the warmth retained by wearing your wetsuit. The other benefits associated with swim caps are to keep longer hair tucked away to avoid potentially impeding the breathing process, help to keep goggles safe and securely fitted for the duration of the swim (especially when placed over the top of the goggle strap) and less resistance through the water by decreasing the resistance that hair would normally create. Again, as many events will insist on you wearing a swim cap, it is strongly advised you become familiarly with wearing one regularly by using them in your training sessions.

Mass group starts

This isn't necessarily a bad section of the swim although it is often feared by many. There are three main ways to conduct a mass group start to an open water swimming event:

1. Running start from the shore into the water

2. Diving start from a jetty / platform

3. Treading water start

The biggest fear can be from being surrounded by so many other swimmers, the unease of knowing which way to go and sense of direction, nerves are high, adrenaline is pumping, etc, etc. Providing they are good at staying on course, surrounding swimmers can assist you in staying on the correct route. They can also offer a good drafting opportunity if you tuck in close to the side of an equally paced swimmer. I would recommend to double check the route and not to always trust the person you follow. Keep your eyes open for anyone looking to break away from a bunch of evenly matched swimmers and do your best to stay with them. You often find that swimming with a group can bring the best times out in your swim. Help each other through it and always be happy to find your own space and swim away from others if necessary.

It is also worth considering Sighting, Pacing, Acclimatisation, Drafting and Sense of Direction.

For more guidance on how to perfect your Front Crawl technique and more download the series of swimming books by Mark Durnford.