There is a moment every summer, usually around the third day of a heatwave, when the flat gets unbearable and the only sensible thought left in your head is water. Innsbruck is unusually good at answering that.

Thirteen lakes, most of them under forty-five minutes from town, several reachable by tram or train without touching a car. Some are warm and shallow and full of families. Some are cold, deep and turquoise and take your breath away in the literal sense.

Here is which one to pick, and when.

BAGGERSEE ROSSAU

The After-Work Dip

Ten minutes on a bike and you are in the water. That is the entire pitch, and on a Tuesday evening in July it is unbeatable.

The Baggersee is not the prettiest lake in this guide and everybody who goes there knows it. What it is instead is close, warm enough at up to 24 degrees, and full of people who had exactly the same idea after work. Half the city ends up there on a hot evening.

In the city. Ten minutes by bike.

LANSER SEE

Where the Journey Is Half the Point

Tram 6, the old Waldbahn, climbs out of the city through the forest and drops you twenty minutes later at a lake with a proper lido. The ride itself is one of the nicest things you can do on a summer afternoon, even before you get wet.

The water sits around 24 degrees, warm enough that nobody has to do the slow, undignified wade-in. There are loungers, a kiosk, and enough grass to find your own corner.

Lans, around 20 minutes. Tram 6.

NATTERER SEE

Loud, Splashy, Excellent With Kids

There is an aquapark with inflatable slides in the middle of the lake, so set your expectations accordingly. This is not the place for a quiet book.

It is the place for a day with children who need to be exhausted, or for anyone who has quietly wanted to throw themselves down an inflatable slide since about 1998. The bus from town gets you there in twenty minutes.

Natters, around 20 minutes. Bus from town.

MÖSERER SEE

Small, Shady and Genuinely Warm

Up on the Mieming plateau, this one gets to 25 degrees, which for an Alpine lake is remarkable. It is small, ringed with trees, and the shade means you can stay all afternoon without cooking.

Take the train and then bus 434. Because it is that bit further out, it never gets the crush that the closer lakes do.

Mösern, around 35 minutes. Train plus bus 434.

REINTALERSEE

The Warmest Water and Sandy Bays

When you want the water to feel like a bath rather than a challenge, drive to Kramsach. Up to 25 degrees, small sandy bays, and the kind of easy holiday atmosphere that makes a Saturday feel like a week off.

Forty minutes down the A12, or by bus if you would rather not drive.

Kramsach, around 40 minutes. A12 plus bus.

WILDSEE SEEFELD

Cooler Water, Board Under Your Feet

Around 20 degrees, so noticeably fresher than the plateau lakes, with a Strandbad and stand-up paddling on the water. When you actually want to do something rather than lie down, this is the pick.

The train up to Seefeld takes half an hour and is a genuinely beautiful ride, which makes this one of the best car-free days on the list.

Seefeld, around 30 minutes. By train.

MIEMINGER BADESEE

Shallow, Warm, Nothing Complicated

Warm and shallow, with a volleyball court and a Kneipp basin for anyone who wants their circulation shocked back into order. It is an uncomplicated family day out and it does not pretend to be more.

Mieming, around 35 minutes.

ACHENSEE

Cold, Turquoise, and Worth Every Shiver

Tyrol's biggest lake, and the one that looks least like it belongs in a swimming guide and most like it belongs on a postcard. The water is properly cold. Going in is a decision, not a drift.

Get there on the Achenseebahn, the old cogwheel steam railway, and the day becomes an outing rather than a swim. Forty-five minutes, and the turquoise is real, not a filter.

Maurach, around 45 minutes. Achenseebahn.

WORTH THE LONGER DRIVE

Five more, all around an hour or a little over, for the days when you have the whole day and want it to feel like a proper trip.

The Blindsee, about an hour away, is emerald and so clear that people snorkel in it. The Plansee, an hour and ten, stretches six kilometres and goes deep and glassy, better suited to a boat than a splash. Its quieter twin, the Heiterwangersee, sits right next door and gets a fraction of the attention. The Rieder Badesee has an island, paddleboards and a strong family day-out feel. And an hour and twenty gets you over the border to the Tegernsee, which is less a lake than a whole Bavarian lake town.

HOW TO DO IT IN A HEATWAVE

Go before ten in the morning or after five in the afternoon. Between those hours in high summer, every lake within half an hour of the city is at capacity and the parking is worse than the crowds.

When you are without a car, four of these work perfectly: Baggersee, Lanser See, Natterer See and the Wildsee in Seefeld. When you want the warmest water, go to Mösern, Kramsach or Mieming. When you want the most beautiful and do not mind the shock, Achensee and Blindsee.

And bring cash. Not every entrance gate takes a card, and finding that out at the barrier in thirty-two degrees is nobody's idea of a good start.

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