There's a business park here in Carlsbad with a nice clear pond that becomes an unofficial dog park on the weekends. Even though there are plenty of NO DOGS and NO TRESPASSING signs,
allegedly the owner is cool with dogs enjoying it on the weekends.
We've had Juno since March and haven't seen her swim yet. With the Del Mar dog beach being a ~20 minute drive south and not knowing how she'd react off-leash with other dogs, we felt a smaller venue would be better for our larger goggie.
The good news is that she took to it swimmingly. Literally. We joined a neighbor and her dogs Ziggy and Salty for a little romp.