The reef sits close enough to shore here that you can swim to it, and the county's rivers and lagoons are calm enough to paddle with children.
The short answer
The best water activities in Palm Beach County are snorkeling the reef at Red Reef Park in Boca Raton, shore diving under the Blue Heron Bridge at Phil Foster Park, paddling the Loxahatchee River from Riverbend Park, kayaking the lagoon from Ocean Inlet Park, and airboat trips into the Everglades west of Boca Raton.
Local's pickRated among the best shore dives in the world: a shallow snorkel trail under the bridge with seahorses, octopus and rays, all from a free public park. Go on the hour either side of high tide for visibility.
Local's pickFlorida's only National Wild and Scenic River, paddled from Riverbend Park through cypress bends to Trapper Nelson's homestead. Rentals are available at the park and the upper stretch is calm enough for beginners.
Jupiter's surf and paddleboard shop, renting boards and running guided paddles on the Loxahatchee River and the inlet. They will tell you honestly whether the surf is worth it that morning.
Airboat rides into the sawgrass of the northern Everglades from the western edge of Boca Raton, 30 minutes from downtown. Morning trips see more alligators and wading birds.
A small county park at the Boynton Inlet with a kayak launch into the mangrove islands of the Lake Worth Lagoon, plus jetty fishing and a snack bar. Manatees are common in the channel.
Boynton Beach's long-running dive operation, running two-tank drift dives on the reef line most mornings and lionfish and lobster trips in season. Certified divers only; snorkel trips run in summer.