Most swimmers think of ear infections as a pool problem. They’re not. Rivers, lakes, and reservoirs carry bacteria that chlorine never touches, and the infections they cause are often harder to shift than anything you’d pick up in a leisure centre. If you swim outdoors between May and September, this guide covers what you’re actually swimming in and why the right earplug makes a genuine difference.

This guide draws on NHS guidance and published microbiology research on freshwater and open water swimming risks. BOLLSEN supplied product specifications and test data for review.

Step 1: Why open water causes more ear infections than pools

Chlorine does one useful thing: it kills most of the bacteria that would otherwise end up in your ear canal. Open water has no equivalent. Rivers, lakes, and reservoirs contain bacteria from soil, animal waste, agricultural runoff, and decomposing matter. After heavy rain, those concentrations spike sharply as surface water pours into waterways.

The main pathogen to know about is Pseudomonas aeruginosa. Pool-related swimmer’s ear is usually caused by Staphylococcus aureus, which typically clears with over-the-counter acetic acid drops. Pseudomonas is harder to shift. It often needs prescription ciprofloxacin drops, and infections can drag on for two to three weeks if you use the wrong treatment.

Surfer’s ear is worth mentioning separately. Repeated cold water and wind exposure causes bony growths inside the ear canal that narrow the passage and make drainage harder. Wild swimmers and sea kayakers training year-round face the highest risk, though most cases develop over a decade or more. Wearing well-fitted earplugs consistently helps with this too.

Step 2: When the infection risk is highest

Heavy rainfall in the 48 hours before a swim is the biggest warning sign. Runoff carries agricultural waste, sewage overflow, and soil bacteria straight into rivers and lakes. Water above 20°C speeds up bacterial growth significantly, which is why river swimming in July is riskier than the same swim in April. Shallow, slow-moving water accumulates more contamination than fast-flowing upland streams.

The Environment Agency’s Swimfo tool lists bathing water quality at monitored sites across England. A 30-second check before you swim is worth it. Sites rated “poor” or “sufficient” carry elevated bacterial counts even in dry weather. For rivers and lakes not covered by Swimfo, check recent rainfall data and scan for nearby agricultural land or sewage overflow notices.

Step 3: Choosing the right earplug for open water

Most swimming earplugs were not designed for open water. Foam plugs compress to fill the canal but offer no real barrier under turbulence. The porous material absorbs water and holds it against the ear rather than keeping it out. Wax plugs form a surface seal at the outer ear but lose it during any dynamic movement. Neither has a meaningful depth rating.

What actually works is silicone with a lamella design. A flat-filter silicone earplug seats inside the ear canal and the lamellas grip the canal walls. The seal holds through jumps, dives, and the natural head rotation of swimming. The BOLLSEN Watersafe+ uses a patented 2-lamella design rated to 3 metres. The silicone is medical-grade, won’t degrade with repeated water exposure, and is trusted by over 1,000,000 people worldwide.

Step 4: Getting the fit right

Fit is where most earplugs fail in open water. A plug sitting too shallowly gets displaced by the first strong wave. A plug in the wrong size won’t seal regardless of the design.

With the Watersafe+, pull your earlobe gently downward with your opposite hand to open the canal, then insert the plug with a slight rotating motion until both lamellas sit fully inside the canal entrance. It should feel like a gentle seal, not pressure. If the plug shifts during a swim, try the next size up. BOLLSEN offers a free AI ear measurement service called AR KI TECH: upload two photos of your ears and the system works out the correct size for your anatomy. It has brought returns down to around 3%.

Put the earplugs in before you enter the water. Once the canal is wet, getting a reliable seal is much harder.

Step 5: Drying your ears properly after every swim

Even well-fitted earplugs won’t keep every drop out during a long session, particularly around the outer ear. Drying your ears quickly after each swim reduces the time moisture sits near the canal, which is one of the main triggers for infection.

Tilt your head to each side and let gravity do the work. Skip cotton buds entirely. They push wax and debris further in, and if the skin has softened from the water, they cause small abrasions that give bacteria an entry point. A clean corner of a dry towel pressed gently against the outer ear is all you need.

Some regular open water swimmers use dilute acetic acid drops (sold as EarCalm at most pharmacies) after each wild swim as a preventive measure. The acidity creates a mildly hostile environment for bacteria in the canal. It is not a substitute for keeping water out, but for people swimming outdoors frequently through summer it can be a sensible extra step. Check with a pharmacist before making it a habit.

Step 6: Recognising symptoms and knowing when to get help

Swimmer’s ear usually starts with itching deep in the ear canal, appearing within 12 to 24 hours of the swim (sometimes up to 72 hours if the bacterial exposure was lower). Most people instinctively scratch, which inflames the tissue further and can break the skin, giving bacteria a direct route in.

As it progresses, the canal swells and sounds become muffled. The ear gets tender when you press the small cartilage bump at the front of the canal. You may notice clear or yellowish discharge. In serious cases the canal can swell shut entirely, causing real hearing loss until it settles.

See a GP if symptoms haven’t improved after 24 to 48 hours, if the pain is significant, or if you run a fever. Tell them you swim in open water. Pseudomonas infections often need prescription ciprofloxacin drops rather than anything from a pharmacy shelf. Left untreated, a severe infection can spread to surrounding tissue. It’s uncommon in healthy adults, but it does happen.

Frequently Asked Questions

Can you get an ear infection from open water swimming?

Yes. Rivers, lakes, and the sea carry bacteria that cause otitis externa (swimmer’s ear). The risk is higher than in chlorinated pools because natural water is untreated, and it goes up further after heavy rainfall and in warm, slow-moving water.

What bacteria cause swimmer’s ear in rivers and lakes?

The most common culprit in open water is Pseudomonas aeruginosa. Staphylococcus aureus and E. coli (especially after heavy rain) are also present. Pseudomonas infections are harder to clear than pool-related swimmer’s ear and usually need prescription ciprofloxacin drops rather than anything from a pharmacy shelf.

What is the difference between swimmer’s ear and surfer’s ear?

Swimmer’s ear (otitis externa) is a bacterial infection of the outer ear canal caused by contaminated water getting in and staying there. Surfer’s ear (exostosis) is bony growth inside the canal from years of cold water and wind exposure. Both affect open water swimmers, but they’re different conditions with different causes and treatments.

Are earplugs safe to use in open water swimming?

Yes, if you use the right type. A well-fitted flat-filter silicone earplug doesn’t block hearing significantly and won’t stop you hearing warnings or instructions. Foam and wax plugs muffle sound more and typically don’t seal well enough to stop water ingress in open water conditions.

How long does swimmer’s ear last without treatment?

Mild cases can clear in under a week if the ear stays dry. Moderate to severe infections, particularly Pseudomonas, rarely go away without treatment and tend to worsen. If symptoms aren’t improving within 48 hours or the pain is significant, see a GP.

What should I do if my ear hurts after wild swimming?

Keep the ear dry and avoid cotton buds. EarCalm (acetic acid drops, available over the counter) can help with very mild early cases. If the pain doesn’t ease within 48 hours, worsens, or comes with discharge or fever, see a GP and tell them you swim in open water so they can prescribe the right treatment.

How do I get water out of my ear after swimming?

Tilt your head with the affected ear facing down and gently pull the earlobe back and up. Jumping on one foot sometimes helps. Avoid cotton buds. If water is still there after an hour, try a hairdryer on a low setting at arm’s length. Don’t put anything inside the canal.

Can swimming earplugs prevent otitis externa?

A correctly fitted waterproof earplug is the most reliable physical barrier between contaminated water and your ear canal. No earplug removes the risk entirely, but a flat-filter silicone design rated to 3m, like the BOLLSEN Watersafe+, gives solid protection across almost all open water swimming conditions.

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