May 29, 2026, 4:12 am | Read time: 6 minutes
When dogs jump into the water on hot days, it initially seems like the perfect way to cool off. However, swimming trips also carry risks that many owners underestimate. From dangerous currents to water intoxication and blue-green algae, a dip in the cool water can quickly become serious. PETBOOK explains what dog owners should watch out for when swimming with their four-legged friends and which mistakes can be avoided.
1. Get your dog used to the water temperature when swimming
“In high outdoor temperatures and cold water, we should first slowly acclimate our bodies to the water to prevent cardiovascular problems and muscle cramps. This also applies to dogs,” says Judith Förster. She is a biologist and pet expert at the animal welfare foundation Vier Pfoten.
2. Keep an eye on your dog while swimming
In the water, it’s important to always keep an eye on your dog. This is especially true if there are currents in the water. Toys should float on the surface, be easily visible, and not be thrown too far. “At a long distance, the dog can lose sight of the toy, search for it in vain, and thus lose strength,” says Förster. “If the animal finds the object easily, it also has a sense of achievement.”
3. Dogs also need to learn to swim
While most dogs can instinctively stay afloat, that doesn’t mean they all swim well on their own. Therefore, it’s worth supporting your four-legged friend during their first swimming attempts. Large and heavy dogs, in particular, tend to sink with their hindquarters. Owners can stabilize the dog by placing a hand under the pelvis. This way, the dog can gradually learn to use its legs correctly and effectively.
Important: Make sure the dog doesn’t spend half an hour in the water right away. Dogs need to train and possibly build up the right muscles for swimming.
4. Watch out for currents
If your four-legged friend is a real water lover, you must pay close attention to which body of water the dog jumps into. Rivers, in particular, can have strong currents—even if they look small. But large lakes can also have currents that are not visible on the surface. This is especially dangerous for small and light dogs. If you’re unfamiliar with a body of water, the dog should initially swim on a leash.
5. Beware of water intoxication
It’s best if the dog has had something to drink beforehand. Because: “Especially animals that bathe in the sea should not drink saltwater, as this can lead to gastrointestinal issues,” says Förster.
But freshwater can also become a problem if dogs ingest too much while swimming. If dogs swallow too much water, it can lead to a dilution of body fluids, affecting nerve and muscle functions as well as blood pressure. Although this phenomenon is relatively rare, it often leads to death.
6. Avoid water tail
The term “water tail” refers to a painful muscle condition at the base of a dog’s tail. It often occurs after the dog has played extensively in the water. While the phenomenon is mainly known after swimming during cooler seasons, four-legged friends can also be affected in summer, especially if it’s windy or the day suddenly cools down quickly.
Since water tail in dogs mainly occurs with high activity in the water, you should warm up your four-legged friend before jumping into the water and take sufficient breaks in between. After swimming, it’s best to thoroughly dry the dog to prevent it from getting cold.
7. Thoroughly dry your dog after swimming
When the dog comes out of the water, thorough drying is essential. This helps prevent skin irritation and matting in animals with undercoats. Also, make sure your pet’s ears are dry to prevent ear infections.
8. Not all breeds can swim
Generally, all dogs can swim. Unlike humans, who must learn the movements, dogs have an innate reflex to stay afloat. However, due to their physical characteristics, some dog breeds are barely or not at all able to swim. Caution is advised, as short-headed breeds like bulldogs can easily drown if they get into the water unsupervised.
Find out which dog breeds are affected in this PETBOOK article: Warning! These dogs can swim poorly or not at all
9. Life jackets for dogs
If your dog belongs to a breed that swims poorly or is not very enthusiastic about water, you can try to get them used to the water with patience and calm—and even support less confident swimmers with a special dog life jacket. According to Vier Pfoten, it’s important that the four-legged friends don’t completely exhaust themselves in the water and can associate the cool water with calmness.
10. Beware of blue-green algae
If you like swimming with your dog in lakes or ponds, you should be especially cautious of blue-green algae infestations in the water, especially in summer. They can cause poisoning in dogs. Depending on the type of algae and contact, the bacteria (yes, blue-green algae are not real “algae” but “bacteria”) can cause various symptoms.
In addition to itching upon skin contact, blue-green algae can cause poisoning symptoms such as vomiting, cramps, diarrhea, or even collapse when ingested. In August, blue-green algae are visible as a green carpet floating on the surface. They are more dangerous before this, when they increase in the water without being visible. Therefore, always check the water quality beforehand.
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11. Where can the dog swim?
Generally, dogs can swim anywhere they are allowed to walk. However, there can be exceptions. There are swimming areas in forests or lakes where dogs are not permitted. Most swimming or beach pools also do not allow dogs. However, there are special dog swimming pools or dog beaches—usually in designated off-leash areas.
By the way: Dogs are not allowed to bathe in fountains, even if this is often tolerated by many municipalities. In case of doubt, fines and warnings may be issued.
Safe swimming fun for dogs and owners
With some preparation and attention, nothing stands in the way of a joint trip to the water. Those who don’t overwhelm their dog, pay attention to water quality and surroundings, and recognize warning signs early can enjoy swimming fun in the summer. Safe cooling is often the best refreshment for dogs on hot days.
With material from dpa