Rancho Del Oro Community Park

I’ve lived in this aria for 10 years and this park has been always here for me. I love it.

Just a very nice park in a very nice neighborhood.

Great park; has plenty of grassy area for kids/​dogs/​kids-​at-​heart to run around in. Also has tennis courts for use (first come first serve).
Note that weekend mornings much of the park is taken up for kids soccer; it can be hard to find parking and/​or free space around then.
During the summer, the city of Oceanside also holds concerts here (usually 3/​year). Fun for the family.
As someone else mentioned, there is not a drinking fountain, although there are restrooms, so if you were desperate, you could likely find water in there. (There is also a YMCA adjacent — that while not affiliated with the park probably wouldn’t let you completely dehydrate.)

Nice little park in the Rancho Del Oro neighborhood. Perfect place if your dog likes to play long distance fetch without interference of many people or activities going on. The grounds are really well maintained, nice short grass, no muddy areas. There are many tennis courts with lots of lights. One bathroom facility. It’s quiet, nice neighborhood. Cons are that the grassy area does not have lights and gets too dark to stay late. Also I can’t seem to find a water fountain anywhere, so if you come with pets make sure you bring a supply. Other than that it’s a decent place in the community.