You can take your dog off-leash in parks, but unfortunately there is not so many of those in the city
Allmend is the most popular location, just next to Sihlcity (map
). It is not fenced, but big enough to either let your dog run freely or use a long training leash. One thing to remember is that the area is divided by the river and while you can do whatever you want in the northern part, the southern is (and should be, but that is another thing...) dog-free.
Another place is Werdinsel (map
), but here you have be careful and not enter the Badi area (also forbidden).
Areas along the Limmat (both directios from Werdinsel) are great for long walks, because sometimes the path gets really wide and there is lots of grass.