A common belief is, that all dogs can and will swim when in water. This is not the case, fact is swimming is not something every dog knows how to do. Some breeds are born swimmers, others can easily learn and then there are those you better keep safe ashore.
Labrador Retrievers, Golden Retrievers, setters are breeds of the first category. These breeds were bred to retrieve fowl out of the water when hunting or for water rescue acts.
Breeds with short legs, compared to their body find difficulty staying above water, e.g. Dachshund. Those breeds with short faces, e.g. Pugs or Bulldogs also face stamina issues in the water, staying above water required a lot of effort. They tire very quickly, so make sure to keep an eye on those even if they love the water.
Other small breeds, e.g. Chihuahua can become very good swimmers, yet are known to be very frightened of the water at the beginning. Be sure to introduce those small breed dogs slowly as stressful fear can cause drowning.
NEVER just ‘throw’ your pooch into the water thinking this will facilitate the process of getting used to it. This can easily lead to panic and cause stressful anxiety, which can lead to drowning or at least a deep-seated trauma. If the dog associated swimming with a traumatic incident it will become even harder to get your pooch to learn to swim again.