Carlsbad Lagoon
Aqua Hedionda Lagoon is one of 3 lagoons in Carlsbad. Known just as the lagoon by locals, this lagoon spans across on either side of the Interstate-5. The inland side of the lagoon is home to the small marina aptly named Snug Harbor. Snug Harbor is located between Tamarack and Cannon road off Interstate 5.
The inland part of the lagoon is where you can boat, water ski, wake board, use your personal watercraft, sail, windsurf or fish. In order to operate any vessel on the lagoon, visitors and residents must meet certain requirements and purchase either an annual or daily permit. Read about lagoon rules.
The Snug Harbor Marina features a boat ramp, dock, snack bar, and a beach. The privately owned California Water Sports, rents water sports equipment and vehicles at the harbor. As far as I can tell the back part of the lagoon has a cut-off area where the speed boats have to stay away. This allows a calmer area for stand up paddle boards and kayaks.
The water from the Pacific Ocean drifts in and out of the lagoon making it a great place to play in the water with your boat or personal watercraft. I have been there quite a few times and besides playing in the water myself, it is always fun to sit back and watch the screaming kids(and some adults) on inflatables flying across the water holding on for dear life.
Regardless of what water toy you have, consider Snug Harbor and the Carlsbad Lagoon for a one day staycation.
t Carlsbad, California.
Staycations California 
Looks like a beautiful place to be.
It is very nice there, thanks.