Barrier Islands

Wild grasses and flowers are in the foreground as a white sand island extends into the distance.
Barrier Islands provide protection for wildlife, plants, and humans.

NPS Photo

Gulf Islands National Seashore protects seven barrier islands. These dynamic bars of sand parallel to the mainland are treasures at the edge of the Gulf of Mexico. The name “barrier” describes how these islands protect natural and human communities against ocean storms. Waves expend their energy as they break on the islands’ beaches. Because they buffer the Gulf’s wave action, barrier islands also protect salt marshes and seagrass beds, which are nurseries for valuable marine species.

Change is constant on these islands. Over time barrier islands move, erode, and grow again as ocean currents and wind gradually shape the seashore. Along the Gulf of Mexico the barrier islands move north and west. Wave action and onshore breezes transfer sand from the south side of the island to the north side of the island. While prevailing south easterly winds set up longshore currents that gradually move sand from east to west. This combination of wind and waves result in the barrier islands moving towards the mainland while also marching steadily westward.

Sand is always moving either by wind, currents, or storms. Sand usually moves from the east to the west, but sometimes change comes suddenly during fierce storms. Extreme weather like hurricanes can profoundly affect barrier islands. Wind, waves, and flooding constantly reshape these islands and frequently damage structures and vegetation. These major storms also cause islands to roll over themselves and migrate to the north.

There’s life on the beach, but it is tough to live here. This border between land and sea offers a place to live for animals that have adapted to these challenges. In the swash zone, where waves break and retreat, there’s a surprising diversity of life hidden under the sand and seaweed. As waves break and the sand heats up, animals hide in materials washed up on the shore, called wrack, or burrow in the sand to survive. Burrowing in the sand protects animals from waves, predators, and extreme temperatures.

Some of these animals are microscopic and live between the individual grains of sand. These animals are known collectively as meiofauna. These small but vital organisms make up the base of the ecological food chain by providing food for larger animals, like crabs living in the swash zone. The crabs are then preyed upon by the fish and birds you see when you go to the beach.


Visit the islands

  • Aerial image of Cat Island
    Cat Island

    The western most island of the national seashore off the coast of Mississippi.

  • A bayou extents in the foreground to trees in the background.
    Davis Bayou Area

    Explore the marshes and woodland areas of the Mississippi gulf shore.

  • A historic cannon sits atop an historic fortification on a barrier island.
    Fort Pickens Area

    Many recreational opportunities, wildlife viewing, and historic sites.

  • Tents set up along a white sand beach, a solitary tree stands near the tents.
    Horn Island

    Located off the Mississippi coast, one of the best wilderness islands in the country.

  • A green tree branch frames a white sand path that leads to blue water in the background.
    Okaloosa Area

    Anchoring the national seashore's eastern end on the Santa Rosa Sound.

  • The sun sets of the Gulf of Mexico with a sandy beach and grass covered dunes in the foreground.
    Perdido Key Area

    One of the most beautiful beaches in the United States.

  • An aerial image of Petit Bois Island.
    Petit Bois Island

    A wilderness island in the Gulf of Mexico just off the coast of Mississippi.

  • The sun peaks over white sand dunes.
    Santa Rosa Area

    Excellent recreational opportunities on beautiful white sand beaches.

  • A digital graphic of islands part of the national seashore.
    West Petit Bois Island

    A small sand island near the Horn Island Pass off the Mississippi coast.

  • A ship approaches Ship Island, a historic fort stands on the island in a distance.
    Ship Island

    Located 12 miles off the Mississippi coast featuring a swim beach and historic fort.

Last updated: April 9, 2020

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1801 Gulf Breeze Parkway
Gulf Breeze, FL 32563

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