How do you swim in the sea when there are waves?

A sea with a bit of swell is one of the joys of summer: lively, bright, full of noise. It is also a different place to the flat blue of a calm morning. Swimming in waves is a skill you build gradually, always on beaches where help is close and always with respect for the days when the sea says no.

Before you go in

The most important decisions happen on the sand.

• Choose a lifeguarded beach. UK lifesaving charity RLSS UK advises choosing lifeguarded venues and knowing your beach flags; the US National Weather Service also says your first choice should always be a guarded beach. Our guide to beach warning flags explains what the colours mean.
• Ask. Lifeguards know where the currents run and how the waves are behaving today. Hawaii's state ocean safety service recommends talking to them before you get in.
• Watch for a while. Waves arrive in sets, with calmer spells between them. Ten minutes of watching tells you a lot about rhythm, where waves break and where the water seems to flow back out.
• Never swim alone. RLSS UK advises swimming with others so someone can help or raise the alarm.

Know when not to go

Some conditions are not for swimming, however good the weather looks.

• Heavy shore break. The US National Weather Service explains that waves breaking abruptly on a steep beach can cause trauma injuries, notably to the neck, even when the surf is not especially big. Hawaii's ocean safety service advises staying out of the water where shorebreak is dangerous and never diving into it head first.
• High surf. Big, powerful waves are dangerous to people in the water and even on the immediate beach.
• Red flags or lifeguard advice to stay out. Follow it, always.

If in doubt, stay out. A paddle in the shallows or a walk along the shoreline is still a day at the sea.

Getting in

Walk in sideways to the waves, so they meet your hip rather than knocking you flat from the front. Keep your eyes on the sea; the NWS advice is never to turn your back on the ocean. When the water reaches your waist, and a wave is about to break in front of you, don't stand and take it on the chest.

Duck under. Take a breath, go under the wave as it reaches you, and come up behind it. Hawaii's guidance recommends ducking under oncoming waves rather than diving into shorebreak. With practice this feels almost restful: the turbulence passes above you.

Once you are beyond where the waves are breaking, the water usually feels calmer: rolling rather than crashing.

Swimming in swell

• Breathe in the troughs. Waves rising beside you can catch a breath. Breathe a little later, turning your head more, or breathe to the side away from the waves.
• Sight often. Lift your eyes forward every few strokes to check where you are. Pick a landmark on shore you can see from the water.
• Shorten your stroke. A quicker, rounder arm action copes better with chop than a long, gliding one.
• Stay close to shore and within the lifeguarded area. Swimming parallel to the beach keeps help near.

If you get tired, roll onto your back and float. RLSS UK's advice if you get into trouble or feel tired is to stay calm and float on your back. If a current is carrying you, Hawaii's ocean safety service advises staying calm, not fighting it to exhaustion, and signalling for help by waving and shouting towards shore. Our guide to rip currents covers them in more detail.

Getting out

Coming in is where many people get tumbled. Watch behind you, wait for a lull between sets, then swim in on the back of a wave rather than in front of it. Once you can stand, walk out promptly, still keeping an eye over your shoulder. If a wave catches you in the shallows, tuck your arms around your head and neck and let it pass.