How do you swim in a straight line in open water?

In a pool, a black line on the bottom does the navigating for you. Take that line away and almost everyone starts to drift, gently curving off towards whichever side their stroke favours. You realise this when you look up after a while expecting the buoy and find a confused-looking paddleboarder instead. The skill that fixes it is called sighting, and it is easier than it sounds.

The basic sight

The idea is to look forward briefly without breaking your stroke.

1. Lift your eyes, not your head. As one arm reaches forward, press down gently with it and lift your face just until your goggles clear the water. Think "crocodile eyes".
2. Glance, do not stare. You are only checking direction. One quick look at a landmark is enough.
3. Turn to breathe. Instead of trying to breathe while looking forward, let your head roll to the side as normal and breathe there. Look forward, then turn and breathe, as one smooth movement.
4. Back to normal. Face down, carry on swimming.

If you only get a blurry impression the first time, that is fine. Take another look a few strokes later.

How often to look

There is no magic number. In calm water with a clear target, every six to ten strokes may be plenty. In waves, wind or when you are near other swimmers or a buoy, look more often. A good test is to notice how far off line you are each time: if you are always correcting a lot, look sooner.

Choose good landmarks

The buoy itself is often too small and too low to see from the water. Pick something bigger behind it:

• A church tower, a tall tree, a distinctive building, a gap in the hills.
• Something with a clear colour, like a red roof or a white lighthouse.
• Two things in a line: if the near buoy and the far tower stay lined up, you are on course.

Have a look from the shore before you get in. Point out your landmarks to yourself for each leg of the swim, so you are not inventing them in the water.

Drift, current and wind

Water moves, and it moves you. A gentle current or a side wind can push you steadily sideways, so that aiming straight at the target leaves you curving down-current. Experienced swimmers aim a little up-current of where they want to arrive and check more often. If you are swimming somewhere unfamiliar, ask locals or lifeguards how the water usually moves before you go, and keep to the rules of the beach or venue. Our page on swimming in waves covers the choppier side.

Practise in the pool

• Sight in the pool. Every few strokes, lift your eyes to a target at the end, like a clock or a flag. Practise until it barely interrupts your rhythm.
• Swim with eyes closed for a few strokes, in an empty lane, to find out which way you naturally drift. Most people have a favourite side.
• Breathe both sides if you can. Many coaches suggest bilateral breathing because it encourages a more even stroke, and an even stroke drifts less. See breathing in front crawl.

A word on safety

Sighting is also how you keep track of where you are relative to the shore, other swimmers and boats. If you are new to open water, safety bodies such as RoSPA and RLSS UK advise swimming with others rather than alone, wearing a bright cap and a tow float, swimming parallel to the shore and choosing lifeguarded or supervised venues where possible; our guide to getting into open-water swimming has the essentials.