Uncle J.
Yelp
It's basically a dog park. And that's fine. The downtown Portland area is running out of parks and really any green space to be able to walk or play with your dog, so it's kind of great that all of the Portland dog loving masses have this. That being said, while it's the only "beach" within city limits, it's not what most people would think of as a proper Maine beach, as it's pretty small, it's not what you would call "pristine", and yeah, dogs everywhere, mostly in the evening (there's a no dogs before 5:00pm-ish law, that some adhere to). And often some crusty dudes standing at the fence behind the beach checking out the ladies sunbathing. Nonetheless, if you don't have any transportation to get out of the city on a hot day, I suppose this is a godsend, and I've had some fun times here after dark (not like that. Mind out of the gutter, people).
I love the path that runs along this for bike rides, etc. and the Eastern Promenade, which sits above the beach, is still the jewel of the city in my opinion. I still like driving 20-30 minutes south to an actual beach on a beautiful day, but we're spoiled in this state with so many options.