Open water swimming for beginners: how to train for your first open water swim

The pool teaches you to swim. It does not teach you to swim in open water. The gap between the two is mostly not fitness, and closing it is a training problem with a clear answer.

Last updated 11 August 2026 · 9 min read

Why open water is harder than the pool

Open water removes almost everything the pool gives you for free: the walls, the black line, the stable temperature and the certainty that you can stand up. The distance stays the same on paper, but the task is much larger.

Each item is trainable once you name it:

• No walls. No push-offs, which in a 25m pool is 3 to 5 metres of free distance every length, and nothing to hang on to. Pool "continuous" swimming contains dozens of micro-rests you never counted. Open water swimming is genuinely continuous.
• No black line. Nothing tells you where you are going, so you have to navigate repeatedly while swimming.
• Chop and current. A modest current makes the swim hard one way and suspiciously fast the other, and chop interrupts your breathing timing.
• Cold. Lap pools sit around 26 to 28 degrees Celsius. A summer lake might be 16 to 20, and coastal water is often colder still. Cold costs energy and, at first, control of your breathing.
• Reduced visibility. In many lakes you see almost nothing below the surface. Some swimmers find this the hardest part, and it has nothing to do with actual danger.
• Psychological load. Depth, dark water and distance from shore add stress, stress raises breathing rate, which raises perceived effort, which raises stress. That loop is why fit swimmers struggle on their first outdoor swim.

So a swimmer comfortable with 1500m in a pool is not automatically ready for 1500m in a lake. They are ready for considerably less, until they have trained the specific skills.

How much should you be able to swim before going open water?

Be able to swim continuously two to three times your intended open water distance in the pool, without touching the wall, before you attempt it outdoors. For a 750m open water swim, that means 1500m to 2250m of unbroken pool swimming.

The multiplier is not padding. Open water distances effectively lengthen, because imperfect sighting means you swim a longer line than the course. Conditions slow you down. And there is no wall, so the swimming has no gaps: a pool 1500m done as 30 lengths includes 29 push-offs and 29 moments of glide, which is a materially easier effort than 1500m without any.

Practise removing the wall advantage while you are still indoors: push off gently rather than explosively, surface immediately instead of streamlining, and do not touch and pause at the turn. If your pool allows it, start some reps from mid-pool with no push-off at all.

Sighting: the skill that saves the most time

Sighting means lifting your eyes just far enough to clear the surface at the front of the stroke, glancing forward, then dropping the face back in. For most beginners, poor sighting costs far more distance than poor fitness does.

The arithmetic is blunt: swim 10 percent off-line and you swim 10 percent further. On a 1500m course that is 150 extra metres, which no realistic amount of extra training makes up. Sighting is the cheapest performance gain available to a new open water swimmer.

The technique:

• Lift only the eyes. Think "crocodile eyes": the goggles clear the water, the mouth stays in it. Lifting the whole head drops your hips and stalls the stroke.
• Do it at the front of the stroke. As the leading hand extends and presses, use that pressure to raise the head slightly, look forward, then rotate into your normal side breath as the face comes down. Sighting and breathing become one movement, not two lifts.
• Every three to five strokes in chop or when the course turns, every six to eight in calm water on a long straight leg. Sighting too rarely is the classic beginner error: you can drift a long way in twenty strokes.
• Aim at something big and fixed. A building, a tree line, a headland. Small buoys sit low, vanish behind waves, and look identical to every other buoy. Use the landmark for direction and the buoy only when you are close.
• Expect two or three looks. One glance often shows you nothing but a wave. Take another on the next stroke rather than stopping to hunt for the landmark.

Practise all of this in the pool, where it costs you nothing: swim lengths sighting forward every five strokes at a fixed point on the far wall. It feels clumsy at first, which is exactly why you want the clumsy phase to happen indoors.

Bilateral breathing and why you swim in a curve

Bilateral breathing, meaning breathing to both sides, matters far more in open water than in the pool, because conditions decide which side is usable and one-sided breathers do not get a vote.

Chop, wind and low sun all come from one direction. If you can only breathe to the right and the waves come from the right, you spend the swim taking water in the mouth or lifting your head to escape it. Swimmers who can switch simply breathe away from the chop.

There is a quieter effect too. Habitual one-sided breathing produces an asymmetric stroke: the pull on the breathing side shortens, the body rotates further one way, and the swimmer tracks in a gentle curve. The lane rope hides this completely in a pool. In open water that curve is exactly the 10 percent detour above, and it is why some swimmers sight correctly and still end up off course.

Building it takes a few weeks: swim your easy aerobic sets breathing every three strokes, and add short blocks breathing every five. Expect the weak side to feel awkward for a while. Our workouts by level guide has sets you can fold this into.

Floating, treading water and staying calm

The ability to stop swimming, float, and get your breathing back under control is the core open water safety skill. It is more important than speed, endurance or technique, and it is the one most pool swimmers have never practised.

In the pool, stopping means grabbing the wall. Open water gives you no such option, so "I got tired" and "I got frightened" both have to be survivable with nothing to hold. Practise in the deep end: tread water for two or three minutes at a time, float on your back breathing slowly, and roll from front crawl into a float without touching anything. Do it until it is boring.

Backstroke is the other tool worth having. Rolling onto your back mid-swim, keeping a gentle kick going and breathing freely is the fastest way to interrupt a rising panic. If your breathing accelerates out of proportion to your effort, roll over early rather than pushing on and hoping.

Cold water, shock and acclimatisation

Cold water shock is an involuntary gasp followed by around a minute of fast, uncontrollable breathing. It is normal, it happens to everyone, and it passes. The rule is simple: get in slowly, get your face wet, and wait it out before you start swimming.

Much of the trouble fit swimmers get into happens in that first minute, when people jump in, gasp, inhale water and panic. Entering gradually, staying where you can stand and splashing the face and neck lets the response run its course while you are safe. Once your breathing settles, swimming feels normal again.

Acclimatisation is repetition rather than toughness: swim in cold water regularly, starting with a few minutes and adding time gradually across sessions. The shock response genuinely blunts, and it fades again if you stop, so the adaptation is not permanent.

A wetsuit helps twice over: warmth, which extends how long you can safely stay in, and buoyancy, which lifts the hips and makes swimming easier. Many beginners are calmer and faster in one for that second reason alone. Get out well before you stop feeling cold, and treat shivering or clumsy hands afterwards as a sign you stayed in too long.

Safety essentials and the gear that matters

The non-negotiables are: never swim alone, be visible, know where you are getting out, and check conditions before you get in. Everything else is comfort.

• A brightly coloured swim cap. Orange, pink or yellow. A swimmer's head in water is almost invisible to a boat, and this is the cheapest fix there is.
• A tow float or safety buoy. It trails on a waist strap, makes you visible from a distance, and gives you something buoyant to hold if you need to stop. It does not make you unsinkable, and it is not a substitute for being able to float.
• Goggles for the light. Tinted for bright days, clear for grey ones. Sighting into low sun over dark water is genuinely hard.
• Known entry and exit points. Identify where you get out before you get in, and pick a landmark beside it, because the shoreline looks different from water level.
• Conditions and tides. Wind direction, water temperature, tide state, local currents, boat traffic. At the coast, a swim that goes out with the tide and comes back against it is a different swim in each direction.
• Swim parallel to shore. For your first sessions stay in waist to chest depth water and swim along the shoreline, not away from it, so you can stand up at any moment. This one habit removes most of the psychological load.

A pool prep set and your first open water session

Two things need to happen before your first open water swim: your pool sessions should stop giving you free rest, and sighting should already be automatic. This set does both.

Your first open water session should have no distance goal at all. The only objective is finding out that the water is fine.

From there, build duration before distance. Add a few minutes of continuous swimming per session, keep to the shoreline until it feels dull, and only then extend into longer point-to-point swims with someone alongside you. If you are working towards a race, our triathlon swim training guide covers how the swim leg fits with the rest of it.

Why your open water pace looks slow, and why that is fine

Open water pace is not comparable to pool pace. You lose the push-offs, you swim a longer line than the course distance, and current and chop take their cut. Being 10 to 20 seconds per 100m slower outdoors is normal and says nothing about your fitness.

This matters practically, because an open water pace figure will quietly corrupt any pool-based benchmark you feed it into. Your critical swim speed depends on repeatable, comparable efforts over known distances, and open water provides neither. A slow open water swim dragged into that calculation lowers your threshold estimate and hands you training zones that are too easy. A current-assisted fast one does the reverse, which is worse.

SwimTune keeps the two worlds separate on purpose. It records open water swims natively on Apple Watch and imports them from Apple Health correctly tagged as open water, and it deliberately excludes open water pace from CSS calculation and personal-best records. Those swims still count towards training load and history, and history can be filtered by venue. To be clear about what it does not do: there is no GPS route recording and no map of your swim, and open water distance comes from the workout the watch measured.

If you are building towards an event, it also has an Open Water Swim Focus training goal, whose plans emphasise exactly what this guide describes: continuous swimming without wall rests, bilateral breathing and sighting, progressing towards your event distance. Open water events run from 1500m to 10km, or any custom distance you enter.

Common questions