Difference Between Gulf and Bay


Main Difference

The main difference between Gulf and Bay is that the Gulf is a larger and deeper body of water than the bay, and it is narrow-mouthed. Whereas Bay is also a body of water that has an opening and, not as enclosed as a gulf.

Gulf vs. Bay

The gulf is a water body that penetrates the land. The land largely surrounds the gulf, whereas land partially surrounds the bay.The gulf is a large water body which is almost covered by land, besides a narrow opening from one side while the bay is a large water body which forms an indentation of the coastline, such as the sea covered by the seashore from all sides. Water abrades deeply into the borderland that makes the shape of the gulf long and narrower. However, the bay has a circular or semicircular shape due to inward land curve. The formation of a gulf is by the movement of the tectonic plates that form deep enclosed water, and the formation of the bay is by abrasion of the coastline, flooding or movement of Earth’s plates.. A gulf has a larger size while a bay has smaller. The gulf is narrow-mouthed as compared to the bay, which has a broader mouth. Greater landmass surrounds the gulf, whereas lesser landmass surrounds the bay. The largest gulf is “Gulf of Mexico” in the world while the largest bay in the world is “Bay of Bengal.” The gulf generally attaches to the ocean while the bay connects to a river or a lake or ocean.


Comparison Chart

The gulf is the body of water that is partially bordered by land.Bay is the large body of water that is largely bordered by land.
Narrow mouthBroader mouth
Formed by movement of tectonic plates and, continental drift.Formed by continental drift, glacial or river erosion and, flooding.
It connects to the ocean.It connects to the ocean, or a river, or lake.
Long and narrowCircular or semicircular

What is Gulf?

A Gulf is a large water body of the sea that penetrates the land. It has a narrow opening with the deep passage of the sea mostly bordered by land and has a narrow opening. A gulf is generally larger and sometimes, also called a large bay. The formation of the gulf is by continental drift and the movement in the earth’s tectonic plates that may split or break apart to form a gulf.. The flow of gulf water deeply abrades the conjoining land. Its shape makes it ideal for ports or trading center in which loading and unloading of cargo and passengers happen using boats. It connects to the ocean. The gulfs which are popular in the world include the Gulf of Mexico, Gulf of Aden, Persian Gulf, Gulf of California, etc. The largest gulf, Gulf of Mexico has a surface area of 1.6 million km² (1,554,000 km²).


What is Bay?

The bay is a recessed water body, partially bordered by land. It is a wide passage of the water body where the land curves inwards. It connects directly to the lake, river, sea, or ocean. A bay is generally smaller with a broader mouth. The formation of the bay is a result of continental drift, glacial and river erosion and movement of tectonic plates. The overflow of the ocean across the coastline also forms a bay. The surrounding land of the bay blocks waves and reduce the force of winds. Therefore, it provides a safe place for fishing. Bays also make good trading centers and ports. The list of popular bays worldwide includes Hudson Bay, Chesapeake Bay, Bay of Bengal, and San Francisco Bay. The Bay of Bengal in India is the largest bay in the world and has a surface area of 2.172 million km². Bays that are opening to the oceans have of marine life and bays that are open to the rivers or lakes consist freshwater and provide habitat to the reptiles. Bays generally have a circular or semicircular shape, and the passage formed in the bay is wide. A bay formed by a glacier is known as a fjord, and a bay formed by rivers is Rias which is characterized by moderate slopes.

Key Differences

  1. The gulf is largely surrounded by land and penetrates the land whereas bay is partially surrounded by land.
  2. The size of gulf is larger. Conversely, the bay is smaller.
  3. The shape of the gulf is longer and narrower. On the flip side, the shape of the bay is circular or semicircular.
  4. The gulf is narrow-mouthed while the bay is broad-mouthed.
  5. The gulf connects to the ocean while bay directly connects to a lake, or a river, or the ocean.
  6. The formation of gulf takes place by the movement of tectonic plates and continental drift. On the other hand, the formation of bay results as continental drift, glacial or river erosion or flooding.
  7. A gulf is more enclosed to the landmass, whereas a bay is less enclose to the landmass.


Both gulf and bay are indentations, but they differ in some ways; gulf is a larger, narrow-mouthed body of water that penetrates the land whereas bay is a broad-mouthed, circular water body that is partially surrounded by land.

Aimie Carlson

Aimie Carlson is an English language enthusiast who loves writing and has a master degree in English literature. Follow her on Twitter at @AimieCarlson