A cove is a circular or oval coastal inlet with a narrow entrance. Colloquially, the term can be used to describe a sheltered bay.

Coves form on concordant coastlines, where rock bands of varying strength run parallel to the coastline. Initially, a narrow band of relatively strong rock, for example limestone or an igneous rock forms the coastline, and behind this is found a band of a weaker rock, such as clays and sands. Waves act on weakest areas of the coast, such as cracks and joints, and eventually break through the strong rock, exposing the weak rock. The weak rock is quickly eroded by wave action, sub-aerial processes and weathering (which causes slumping). A circular shape is formed because wave diffraction occurs where waves travel through the narrow entrance and then disperse in the cove, causing equal erosion at all points of the cove shoreline. Often, another band of strong rock, such as limestone or chalk forms the back of the cove. Coves are generally found on islands and in warmer climate locations.

A good example of a cove is Lulworth Cove on the Jurassic Coast in Dorset because just west of it a second cove, Stair Hole, is forming.