The “pirate playground” is located in the pedestrian-only section of Boernergasse, accessible by the 35A bus (either “Kratzlgasse” or “Gustav-Pik-Gasse” stop and a short walk up Boernergasse) or the 39A bus (“Daringergasse” stop and a short walk up Boernergasse). This is a city park but it’s not marked on city or Google maps as such.
The highlight of this playground is a wooden pirate ship that the kids can climb around: it has a rope ladder, bridge, and slide. The playground also has a rope swing, bouncy see saw-type thing, zip line, and covered sand pit. Thankfully the water pump is outside the playground gate, which means the sand is likely to remain sand. The park has some shade and a couple benches, but neither bench was in a shaded area.