I think is an islet.
sandbar
intertidal zone
A shoreline indentation is called a bay. It is a curved area of water partially surrounded by land, often less exposed to the open sea than a gulf.
The firm ridge of sand that appears off the main shoreline due to ocean wave weathering is called a sandbar. Sandbars commonly form in shallow coastal areas where waves displace sand and create an elevated ridge above the water surface.
A ridge of sand that runs parallel to the shore is called a sandbar. Sandbars are typically submerged or partially exposed at high tide and can be an important habitat for marine life.
The new name for a sandbar is often referred to as a "sapropel." However, in specific contexts, it might also be called a "shoal" or "sandbank." The terminology can vary based on geographical location and the specific characteristics of the sandbar in question.
If the land is connected to other land, it is called a peninsula, but if its a piece of land on water by itself it is an Island.
Such a feature is known as a sandbar.
it is called a sandbar
The shallow extension of the continent that extends beyond the shoreline is called a continental shelf. It is the submerged part of a continent that extends from the shoreline to a drop-off point called the shelf break.
it is a underwater dune made by waves.
Cove