The honest answer: swimming is a Pug's weakest event
Some Pugs enjoy paddling and a few swim with real determination, but as a breed they are built against the water in almost every way. The Pug's flat face narrows the airway, so breathing is already harder work than in a long-muzzled dog, and exercise, excitement, and heat all raise the effort further. The body is dense and front-heavy, with a big chest and head carried on short legs, so a swimming Pug tends to tip nose-down, paddle frantically to keep the face clear, and tire in a fraction of the time a leaner breed manages. Enjoyment, where it exists, must be wrapped in strict limits.
Why wading beats swimming for this breed
For most Pugs, the right water activity is standing-depth wading in a shallow entry pool, a gentle shoreline, or a paddling tray, where the feet stay on the ground and the face stays dry. Cooling comes easily this way too, which matters because Pugs overheat readily and water play is often suggested for exactly that reason; a wet belly and wet paws cool a Pug without any of the breathing load of swimming. If your Pug does swim, it should be in a properly fitted life jacket chosen for a broad chest and short neck, over a distance of a few body lengths, ending well before the breathing grows louder or the strokes slow.
Rules that keep a Pug safe near any water
Never let a Pug near a pool, dock, or deep shoreline unsupervised, even one who has swum before, because a dog who slips in quietly may not manage a single length or climb out at all. Stay within arm's reach during any paddle, watch the breathing rather than the tail, and bring the dog out at the first sign of louder, harder breathing, wide-eyed effort, or a rear end sinking so the face tilts up. Offer drinking water and shade between dips, keep sessions on hot days very short, and dry the facial folds and ears afterwards, since damp folds are a Pug's familiar trouble spot.
The warning signs that mean a veterinarian now
Breathing trouble is the emergency this breed teaches you to respect. A Pug who comes out of the water gasping, breathing noisily at rest, coughing repeatedly, or who seems weak, wobbly, or unusually quiet after swallowing water needs veterinary care immediately, not a rest and a re-check in the morning. The same applies to any Pug who was submerged, even briefly, and then seems subdued. When you call, say plainly that it is a flat-faced dog with breathing difficulty after water; that sentence moves the conversation to the right urgency.
Assigning the Pug water watch
Pug water safety fails most often through diffusion of responsibility, when several adults each half-watch a pool and nobody owns the dog. Naming one person per outing as the dedicated watcher, and setting that duty out in KinsLe Care Teams alongside the vest, wading-only, and breathing-watch notes, gives your Pug a single accountable pair of eyes and a written routine the next watcher can pick up unchanged.