Big Lagoon County Park sits seven miles north of Trinidad on a sand spit stretching from Agate Beach, where the real draw is hunting for semi-precious stones like agates, jade, and moonstones while your dog explores the shoreline. The lagoon itself stays calm and shallow, which makes a huge difference if your dog enjoys water—you get that refreshing swim experience without the pounding Pacific waves that crash just offshore. It’s genuinely safer for dogs than the open ocean beaches nearby, though the lagoon does get busy during peak season, so you’ll want to keep your dog close and watch the currents.

If you want to see the lagoon from the water, Kayak Zak’s operates rentals from the boat ramp and includes a mini-lesson with each kayak. They’re available daily from Memorial Day through Labor Day, and it’s a nice way to experience the area without having to swim. Outside those months, call ahead since availability drops.

The park has hiking trails winding through the landscape that give your dog good stretching room, though you’ll need to keep your dog leashed since wildlife is present throughout. The trails aren’t strenuous—they’re more about wandering through the green spaces and letting your dog get their sniffing in rather than serious hiking.

The real magic here is the combination: you get the beach treasures, the safe water environment, the trails, and the relative quietness compared to more famous coastal spots. It’s the kind of place where you’re not fighting crowds of other visitors, and your dog has room to actually move around. The sand spit setting creates its own little protected ecosystem, so you’ll notice the environment feels different from other Northern California beaches. Bring layers since ocean wind picks up, even on calm days, and plan for a few hours to really explore both the beach and the trails without rushing.