Howard Heuston Park

This park gets three stars for convenience (I can walk there from my place), and because it is the fastest way to wear out your pooch after work.
The off leash area isn’t huge, maybe the size of a football field, but the grass is lush and nice and it borders a creek, which is always full of good smells (this is more of a drainage than a creek, so unless you were planning on giving Fido a bath I wouldn’t recommend swimming here).
However, between about 5:30 and 7:30 on weeknights this place is doggie happy hour. There are dozens of dogs, ecstatic to see each other, running around and slobbering everywhere.
If you don’t have time to take your pooch elsewhere and need to wear him out after work, this park offers a quick fix.