Bay, harbor, port, wharf, cove, and some other similar terms are often used interchangeably. Because of this, it can be hard to get an idea of what a bay or harbor actually is, or if there’s any difference at all. Bays and harbors are two distinct bodies of water, and each has its own qualities that define it.

Bay vs Harbor

Location, Size, and Shape

A bay is defined as a large, recessed body of water. This body of water must be connected to a main body of water, such as a lake, sea, or ocean.

The entrance from the bigger body of water into the bay is usually relatively narrow, but it’s not enclosed.

The easiest way to spot a bay on a map or while you’re out boating is to look for an indented section of shoreline with a relatively large body of water behind it.

an open bay next to a road and buldings

From above, a bay looks something like a rough semicircle, although not all bays are circular. If you were to draw a circle around the edge of a bay, the opening should be the width of the circle’s diameter.

If this opening is too much wider or smaller, it’s not truly a bay.

The difference between a bay, a gulf, and a cove is somewhat murky. Bays, coves, and gulfs are all types of inlets. A cove is simply a small bay, so you could call a cove a bay or call a small bay a cove.

A gulf is larger than a bay, and the mouth of a gulf is narrower, comparative to the size of the inlet, than that of a bay. A bay can also be contained in a larger bay.

A harbor isn’t as recessed as a bay, and its shape is generally not nearly as circular. Harbors do not have an indented shoreline, but they are almost completely surrounded by land or another barrier.

Harbors are also sometimes called wharves. Harbors or wharves can be contained in a port, which is simply a location for stopping when on a boat. Ports often have several harbors with different purposes or accommodations.


Harbors are a bit like a parking lot for boats. Boats require safe spaces with calm waters to dock when they’re not being used.

Water that is exposed can become rough during storms or even inclement weather, and this can lead to damaged boats and docks.

The barriers that surround a harbor, however, generally block the worst of the wind and waves, creating a small, secluded space that offers calmer waters.

Bays don’t necessarily have a specific purpose. They can, however, be useful, particularly when it comes to boating, shipping, or fishing.

Because bays are recessed, the water in a bay is often calmer than the water in the larger ocean, sea, or lake. This makes bays a good location to set up a port or harbor.

The water in bays is also sometimes warmer. This, combined with the relative calm of the water, makes a fantastic habitat for sea creatures, including corals and a range of fish.

Fishing in a bay, therefore, is often much more plentiful, although the catches might be smaller than fishing out on the ocean.


Bays are almost always formed naturally. As the larger body of water wears away at the rocks and soil of the shoreline, a bay forms. This can take thousands of years, and most bays don’t drastically change in shape, even over the span of hundreds of years.

large harbor with parked boats

Harbors can also form naturally, although they do not, of course, form with the specific purpose of safely harboring boats. Many harbors, however, are created by people to serve just that purpose.

If a stretch of shoreline is located near a major city or has calm waters that make it a good location for a port, people look for a harbor. If there isn’t one already, a harbor can be made by filling in certain areas or constructing barriers.

What is a channel, fjord, strait, sound, or bight?

Channel, fjord, strait, sound, and bight are other common terms used for bodies of water. A channel is a narrow stretch of water between two bodies of land.

One of the most well-known channels is the English Channel, which is a section of the Atlantic Ocean between England and France. It connects to the North Sea.

A fjord is similar to a channel. A fjord is also a narrow stretch of water, but it’s usually an inlet that runs between cliffs or very large slopes.

A strait is a narrow passage between two landmasses that connects two oceans or seas. Straits can also connect large lakes, either to each other or to other bodies of water.

Straits tend to be smaller than channels. They are often part of a channel, and they’re generally found at the most narrow point between the two landmasses.

A sound is one of the hardest nautical terms to define. Sounds are simply smaller bodies of water that connect to an ocean or sea.

This means that any small body of water, including a harbor, bay, or cove, could be called a sound, but some areas that don’t fit these definitions are also called sounds.

A bight is similar to a bay or cove. It is a curve in a coastline. Most bights are relatively small, but some are quite large and can run for miles. Bights have a gentler curve than bays, and they’re not usually as recessed.

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