Tidepools and Intertidal Rock Flats

a person wearing water shoes squats down next to a tidepool. A vast stretch of rocky tidepools can be seen in the background. — Tidepooling is a great land-based activity in Florida Keys National Marine Sanctuary to witness the wildlife that inhabit intertidal zones. Photo: NOAA

In the Florida Keys, the ocean's edge tells a story written in ancient coral limestone. During low tide, shallow depressions and eroded grooves in the exposed Key Largo Limestone and Miami Oolite create small, temporary pools of seawater. These limestone tidepools and intertidal rock flats provide shelter for marine life adapted to changing conditions of temperature, light, and salinity.

Within these warm, sunlit basins, visitors may find juvenile fish, gobies, chitons, small crabs, nerites, and sponges—species that thrive in the calm, nutrient-rich waters left behind by the receding tide. Though modest in size, these habitats play a role as nurseries and transition zones, linking the mangroves, seagrass beds, and coral reefs that define the Florida Keys National Marine Sanctuary ecosystem.

Tidepools are most easily observed near natural rock ledges or historic shoreline structures, such as remnants of the Overseas Railroad, where ancient coral formations meet the sea. Visitors are encouraged to follow tips for good tidepool etiquette and wildlife viewing guidelines. Enjoy a rare glimpse into one of the sanctuary's most delicate and dynamic environments!

a brown, oval critter with many overlapping plates is slightly exposed in a shallow limestone rock tidepool. — A chiton clings to exposed limestone in a shallow tidepool at low tide in Florida Keys National Marine Sanctuary. These armored mollusks graze on algae that grow on rock surfaces. Photo: Rachel Plunkett

white mangrove illustration — Small crabs like this one can be found within tidepools in Florida Keys National Marine Sanctuary. Photo: Rachel Plunkett/NOAA