Bred for the trail, not the lake
Beagles sit in the middle on swimming. Individual dogs range from happy paddlers who wade in belly-deep on a hot day to confirmed land dogs who skirt every puddle, but the breed as a whole was not developed for water. A Beagle is a scent hound, built to put his nose down and follow a trail across fields for hours. Nothing in that job selected for a water-repellent coat, webbed feet or a retrieving instinct, so swimming tends to be something a Beagle tolerates or learns to enjoy rather than something he seeks out.
That makes the introduction matter more than the breed label. A Beagle introduced gently, in warm shallow water with his feet touching the bottom, often decides splashing is fun. One carried into deep water will likely remember the fright every time he sees a lake.
How a Beagle actually swims
Beagles can swim — the paddling instinct is there — but their compact, solid build and short coat make them unremarkable at it. Sessions should be short, in calm water, with an easy walk-out exit. A canine life vest is worth using for boat trips or deeper water, both for buoyancy and for the handle on the back, which makes lifting a wet, wriggling Beagle far easier. Never let a Beagle swim in fast current: he has neither the power nor the water drive to fight it, and his instinct will be to head for a smell on the far bank.
That nose is the real safety issue at the water's edge. A Beagle who catches scent of rabbits or food across the water may simply set off, deaf to calling. Keep a long line on in unfenced swim spots, however good his recall is on land, because scent plus water is the combination that overrides training in this breed.
Heat, ears and the famous shake
Where swimming does help a Beagle is summer cooling. A short paddle on a hot walk lets him regulate his temperature without the overheating risk of midday running, and many Beagles who refuse a formal swim will happily stand in a stream. Afterwards, dry those long, heavy ears carefully. Beagle ears hang close and trap moisture in the canal, and repeated wetting without drying is a common route to irritated, scratchy ears in the days after a swim.
Expect the shake — Beagles hold a surprising amount of water in that dense coat and will deposit most of it on whoever is nearest. A towel before he gets in the car saves the upholstery and his dignity.
Reading your own dog
Watch the first two or three water encounters and believe what you see. Ears up, tail wagging, volunteering back in: you have a swimmer, and short regular paddles can become part of his exercise. Tucked tail, scrambling for the bank, avoiding the shore path next time: you have a shore dog, and a paddling pool in the garden is a kinder ceiling. Recording which camp your dog falls into saves the next family member from repeating the experiment, and KinsLe Family Sharing keeps that note on your Beagle's profile where everyone planning his walks can see it.