On the lake in Pregny along from Jardin Botanique

One of the more tranquil and close "beaches" to Geneva is opposite and along from the Jardin Botanique.  I don't know the name of this little park but in has a good buvette and restaurant. The Restaurant Reposoir serves drinks, ice cream, snacks and meals on some very comfy sofas.

The beach  is some sloping concrete but none the less you can paddle.

I've added a new tag Lake Side for playgrounds on the lake.

McLHCb Near Ferney

The new well-known Scottish restaurant is now open just inside France over the Mategnin border. The restaurant and outdoor playground are situated close to LHCb which is one of the four LHC experiments at CERN. You can eat your burger and watch them play while the big bang is recreated under your feet.

View Mt Blanc while climbing on Salève

The Salève is the 1400m mountain right next to Geneva. It's easy to reach with public transport and then can be scaled with the cable car or alternatively you can just drive up. Apart from the obvious walking and view-taking to do there is a small see-saw at the kiosk at the top of the cable car. The Auberge des Montagnards in Croisette has a terrace and small climbing frame (which is reassuringly close to the restaurant's tables) looking out to Mt Blanc, they also have chickens and rabbit as a useful diversion.

Fly the Plane in Petit-Saconnex

This plane and climbing frame are in a school in Petit-Saconnex so visit out of school hours. Nearby is probably the oldest restaurant in Geneva, fondue of course. Just past the playground is an impressive vegetable shop also.

The Icosikaioctagon at Bois-de-la-Bâtie

Bois-de-la-Batie is some woodland right in the middle Geneva affectionately known as Batty Woods. The climbing frames are big, there's an Octopus, a wooden train and a paddling pool with fountain frogs. Within the woods there is an extensive animal park with goats, rabbits, wild boar, chamois, peacocks, .... On a practical note, there isn't a cafe at the park that we know of, so if you are planning to stay a while bring a bait box.

Springy Bull-rushes at Parc de Mon Repos

Parc de Mon Repos is the park by the lake on the way to the botanic gardens from Geneva. It looks to be good for summer with water channels and dams. There is also a recently renovated paddling pool.

As well as a strap in swing there are some springy bull-rushes, which actually look a lot better than they really are.

The nearby History of Science Museum is a great place to visit with children.

Bouncy Castles at Palexpo

Palexpo is the Geneva exhibition centre near the airport normally reserved for the likes of the Geneva Motor Show. In the winter months, however, one of the halls is taken over by Espace Junior.

The room is filled to bursting with bouncy castles, I counted at least 20 in total. There are also trampolines, battery go-karts and self propelled vehicles for the younger ones. This year the charge was 12 CHF for each child and adults were free, the go-karts require an extra token. There's a small shop selling ice-creams, coffee and beer. They have tables and benches to allow you to bring your own food or even host a children's birthday party.

Certainly this place has to be visited at least once over the winter season.

Secret Aeroplane Park in Ferney

This park is uniquely located right up against Geneva Airport's runway. From the climbing frame you can view private jets and huge boeings roar in right next to you. The park is a nature reserve and there are often plane spotters sitting on the many benches overlooking the runway.
I particularly like the merry-go-round and its ability to make you feel quite sick while you attempt to demonstrate conservation of angular momentum.
To find these swings park by Lidl supermarket and head through the gate in the fence past the large ponds.

Adjacent to Carouge's Museum

Just by the museum in Carouge is small but perfectly formed park. It's a short walk from the excellent Saturday market place here. Go through the gap in the stone wall to find the park.

Indoor Play In Carouge - Wolfisberg

Wolfisberg is a laid back and sophisticated bakery and cafe, it's good for coffee, lunch or a drink. Children are well catered for with a climbing frame sensibly separated from the diners by a sheet of perspex - fabulous!