Imagine having only one day of the year when you are allowed to swim.

So it goes for the city’s dogs.

They are banned from Toronto’s public pools until the very last hours of the last day of the season, when they’re finally invited in for a short dip at 10 of the outdoor pools before they are drained and cleaned. All they need is a chaperone — a human aged 18 or older — and proof of vaccinations.

The event went ahead as scheduled on Sunday afternoon at Stanley Park, near King and Bathurst Sts., despite the threat of rain. It kicked off with a chorus of barking as about 20 dogs turned up — from chihuahuas to Great Danes — for their turns to jump in and doggy-paddle their way through the afternoon.

A massive black and white Great Dane named Rorschach — “Rory” for short — was tentative about jumping in the water even though he enjoys swimming, said his owner, Jessica Fernandes, who noted that this is the second year they’ve attended.

After a good push, Rory swam a length of the pool, although he seemed to prefer running laps around the deck.

A 200-pound Leonberger named Grimsby contentedly swam laps while his owner, Art Vindasius, attempted to lure him back on the pool deck with tennis balls. Grimsby was uninterested, preferring to stay in the water.

A golden retriever named Pika also did laps, chasing tennis balls heaved by owner Annie Le.

“This is our first year. We saw it on Facebook,” Le said, noting that this was Pika’s first attempt at swimming in a pool after having been in the lake a couple of times.

“We were kind of afraid he wouldn’t know how to get in and out,” Le said.

She needn’t have worried. Pika jumped in repeatedly, rescuing a green tennis ball and orange Frisbee from the pool.

Things didn’t go quite so swimmingly for Marley, a Boston terrier who jumped in, only to find that the water was too deep.

His owner, Maria Belmessova, became the only person to share the pool with the dogs on Sunday when she jumped in after him — fully clothed — for the rescue.