Florida Bay

Florida Bay is one of the most important waters in Florida. It’s located south of the Florida Everglades and Everglades National Park.

On the west, Florida Bay is bordered by the Gulf of Mexico. To the East and south, it is bordered by Islamorada, Key Largo and the Florida Keys.

Florida Bay covers more than 1,100 square miles (2,850 km). Almost all of Florida Bay is contained within Everglades National Park.

How Deep is Florida Bay?

The Florida Bay is very shallow and consists of a series of shallow, partially connected basins. The bay sits upon a shallow shelf which is part of the Florida Plateau.

The area is filled with mangrove forests, large fields of seagrass, sandbars and mudbanks, which constrict water flow.

Why is Florida Bay Important?

Florida Bay is a critical ecosystem, and is important for many reasons.

The South Florida ecosystem supports an immensely diverse population of native wildlife, including important, rare and endangered species. The South Florida ecosystem is home to manatees, American crocodiles, American alligators, sea turtles and countless other species.

Florida Bay also supports important economic interests, including tourism, fishing, agriculture and other interests.

The area is an important estuary. Enormous sheets of fresh water flow south from the state of Florida, through the Everglades, and meet the salty water of the Gulf of Mexico. In the past, before human intervention, the volume of fresh water ingress was much larger.

Like all of Florida’s waterways, Florida Bay is constantly under attack from many directions.

In recent decades vast amounts of water have been diverted because of development, commercial and industrial interests.

In the past 100 years, the amount of fresh water flowing through the Florida Everglades has been cut by approximately 50%.

As water flows have diminished, many environmental problems have arisen, like hypersalinity and seagrass die-offs.

Florida Bay Research

Extensive research is ongoing in Florida Bay and the South Florida Ecosystem.

Among other areas of interest, the Florida Bay area is monitored to understand important environmental questions:

  • The impact of various environmental factors on Florida Bay: storms, climate change, changes to freshwater flows, changes to the water cycle, evaporation and precipitation.
  • The effects of changes in nutrient concentration, oxygenation, nitrogen levels and other factors.
  • The cause, severity and impact of harmful algae blooms, and the dynamic interplay between other conflating factors.
  • The interplay between native wildlife species and environmental factors.
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Florida Bay Depth

Florida Bay is generally very shallow.

The Bay consists of a series of bowls and basins, which are separated by sandbars, shoals, banks, islands and shallow areas which can be only a few inches deep.

To travel from one basin to another, boaters must navigate through complex paths and channels of deeper water.

Many of these paths are only inches deep, and are all exceptionally difficult to navigate. This is especially true during the winter dry season, when water levels are even lower.

It is very easy to accidentally run aground, or cause damage to the shallow seabed.

Many areas are inaccessible at low tide, or even during high tide. The area is a maze of shallow water obstructions.

Experienced boaters often use clues in the water to assess water depth. Helpful signs include wading birds, trees, mangroves, markers, and the water’s color.

In general, blue and green water is deeper, and brown water is shallower.

Deep and shallow water are also affected by wind and currents in different ways, so a trained eye may be able to identify shallow water by those methods.

For example, in choppy conditions, shallow water may appear more calm than surrounding water.

Polarized sunglasses and lenses can be helpful for identifying shallow water.

If you’re not sure whether you can or should approach or enter an area, don’t. It’s best to avoid it altogether.

In some areas, manual, human propulsion is advised. In shallow water, manual push-poles can prevent damage to vessels, the environment and prevent wildlife trauma.

Boaters should be exceptionally careful not to run aground, as it can damage both their vessel and the sensitive underlying seafloor and seagrass. Boaters should use proper motor and propeller trim at all times.

If your propeller wash is white, that is generally a good sign, and indicates that your propeller is not damaging the sea floor.

Brown propeller wash indicates that your trim is set too low. The brown color occurs because the propeller is disturbing the underlying seabed, and blasting it with a powerful stream of water.

If you find vegetation in your propeller wash, it is a serious problem. It means that you are actively damaging the seafloor vegetation, sea grass, and organisms that live on the seafloor.

Florida Bay Islands

Florida Bay is filled with thousands of sandbars and small islands. Because of the high number, it is one of the largest collections of islands in Florida. Most other islands in Florida are larger barrier islands.

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Islands in Florida Bay often sit just above the water. They are one of the only sources of dry land, and provide important habitats to animals, plants and trees.

These dry islands are especially important for indigenous trees in Florida. Mangrove trees and other native vegetation help provide important root structures, and help prevent soil erosion during flooding.

Native Wildlife

Florida Bay, and the Everglades, are unique and important habitats.

These ecosystems are home to a high concentration of Florida’s native wildlife, including endangered species like the Florida Panther, American Crocodile, and many others. 

Florida Bay is one of the only places in the U.S. where fishermen can catch bonefish, tarpon, snook, redfish, and other species in one place.

It also provides an essential habitat for a variety of birds, including migratory birds and endangered species.

Florida Bay, and the Florida Everglades, are also one of the only places where alligators and crocodiles coexist together.


Florida Bay has some of the largest sea grass beds in the entire United States. Seagrass plays an important part in the Florida Bay ecosystem in a variety of ways:

  • Seagrass leaves help trap sediment in the water and reduce turbidity.
  • Seagrass root structures help prevent erosion and stabilize seabeds.
  • Seagrass provides shelter and protection for marine life, including fish, crustacean and shellfish.

Seagrasses also form the base of the food chain, which sustains many other forms of life, including manatees.

Manatees, sea turtles and other species rely on seagrass for their primary food source. Dolphins and birds use sea grass areas as productive feeding grounds. Seagrass can also provide a base for algae and small organisms to live on.

Several types of seagrass are found in Florida waters:

  • Turtle grass
  • Shoal grass
  • Manatee grass
  • Widgeon grass


Mangroves are essential to Florida Bay, the Florida Everglades, and all of Florida.

The mangroves serve a variety of important functions. Just to name a few:

  • Root structures provide cover and habitat for marine organisms and juvenile fish
  • Mangroves absorb wind and wave energy, and reduce the effects of storm surge
  • Root structures help prevent erosion

Everglades Weather and Seasons

The Florida Everglades are affected by two seasons: wet and dry seasons.

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Rainy Season

The wet season lasts from April to November, when hot and humid conditions produce large amounts of rainfall.

The wet season brings many bugs, mosquitoes, heat, and humidity. During the wet season the area is often affected by hurricanes, which dump large amounts of rain on the region.

There are also afternoon storms, which occur almost daily. These storms also dump large amounts of rain onto the Everglades and surrounding watershed.

Large amounts of fresh water are important to help maintain stable and healthy salinity levels in Florida Bay, among other things.

Dry Season

The dry season lasts from November to March.

During the dry season, Florida receives much less rain, and humidity levels are relatively lower than during the wet rainy season.

Bug and mosquito activity are lower. Water levels in the Florida Everglades and Florida Bay are lower during the dry season. This makes boat access more difficult.

The Florida Everglades National Park is one of eleven national parks, preserves and monuments in Florida.

There are three national parks in Florida. They are all located in south Florida.

Everglades National Park

The Florida Everglades, and Everglades National Park, cover a large area; they cover more than 1.5 million acres, and form a large part of the Florida Peninsula.

Most of the Everglades ecosystem is not accessible to visitors.

The northern section of the park can be accessed via Miami from the east, or Everglades City on the western portion of the park.

The southern section of the park is accessible via Homestead.

Additional Resources




Florida Sea Grant



Florida Fish and Wildlife

Florida Keys National Wildlife Preserve

Everglades National Park

University of Florida

Florida Museum

Southwest Florida Water Management District (SWFWMD)

Cover Image courtesy of Florida FWC, CC2.0