Wild Swimming with Your Dog

The ideal wild swimming location for a dog has calm or slow-moving water, a gentle entry and exit point, good visibility of the water so you can see hazards, no blue-green algae warnings, and legal access. Lakes and tarns are excellent but watch for algae, cold thermoclines and hidden drop-offs. Slow rivers are good, but currents are stronger than they appear and there may be submerged debris. Fast rivers are poor and dangerous because of strong currents, weirs and entrapment hazards. Sheltered sea bays are good, but mind the tides, rip currents, jellyfish and saltwater ingestion.

Access law is important to understand. In England and Wales there is no general right to swim in rivers or lakes — access depends on the landowner's permission or specific local bylaws. Many rivers and lakes have long-established informal access, but this is not a legal right. Scotland's Land Reform Act gives much wider access to water. The Wild Swim Map and the Outdoor Swimming Society are excellent resources for finding legal, well-regarded spots across the UK.

Before every visit, check for blue-green algae. This is one of the most serious hazards for swimming dogs — the toxins it produces can cause liver failure and death within hours of ingestion. It is most common in warm, still water during summer and early autumn, and often looks like green paint, foam, or pea-soup scum on the surface. Check the Environment Agency's Swimfo website and your local water authority. If there is any doubt, do not enter the water and do not let your dog in either. There is no safe level of exposure.

Cold water is the most underestimated hazard in wild swimming. Water below 15°C causes cold water shock — an involuntary gasp reflex that can cause inhalation of water and, in severe cases, cardiac arrest. Dogs are not immune to this. Acclimatise gradually: wade in slowly, let your dog enter at their own pace, and never allow a cold plunge from a height. Hypothermia is a real risk in UK waters, particularly in spring and autumn; signs include shivering, lethargy, muscle stiffness and pale gums.

River currents are consistently stronger than they appear from the bank, and even a gentle-looking river can have powerful undertows after rain. Weirs are extremely dangerous — the recirculating hydraulic below a weir can trap and drown both dogs and humans, so never swim near one. In the sea, always check tide times before you go, and be aware of rip currents, which are often invisible but can pull a dog rapidly offshore. If your dog is caught in a rip, do not fight it directly; angle across it towards the shore.

Leptospirosis (Weil's disease) is a bacterial infection spread through the urine of infected animals, particularly rats, and is a serious risk for dogs that swim in rivers, canals and lakes. Ensure your dog's leptospirosis vaccination is up to date and keep it current with annual boosters. The vaccine does not cover all strains, so even vaccinated dogs should not drink from natural water — always offer fresh water instead. Other hazards to be aware of include giardia, swimmer's itch, discarded fishing hooks and line, and boat traffic.

Rinse your dog with fresh water after every swim to remove algae, bacteria, salt and any chemical pollutants from their coat and skin. Pay particular attention to the ears, which trap water and are prone to infection, and the paws, which may have picked up debris. Dry your dog thoroughly, especially in cold weather — a wet, tired dog loses heat rapidly and is at real risk of hypothermia if left wet in a cool breeze.

Swimmer's ear (otitis externa) is common in dogs that swim regularly, because trapped water creates a warm, moist environment that bacteria and yeast thrive in. After every swim, gently dry the outer ear with a soft cloth, but never insert anything into the ear canal. If your dog is shaking their head, scratching at their ears, or you notice a smell or discharge, see your vet. Do a thorough tick check too, and watch for signs of illness in the following days — lethargy, loss of appetite, vomiting, or jaundice can indicate leptospirosis or other waterborne infection.

Know your water emergencies. For near-drowning, get your dog out immediately and hold them with their head lower than their body to drain water from the lungs; if unconscious and not breathing, begin canine CPR (30 chest compressions to 2 rescue breaths) and get to a vet as fast as possible, because secondary drowning can occur hours later. For suspected algae poisoning — vomiting, seizures, collapse — this is a life-threatening emergency; do not wait for symptoms to worsen, get to a vet immediately and tell them your dog has been in water with suspected blue-green algae.