This habitat type includes underwater shoals – low oblong sand embankments with an asymmetrical cross-section, accumulated by waves. In Estonia, this habitat type is deemed to primarily include the shallow sea with a sandy bottom up to the lower distribution limit of vegetation, which is usually 5–15 metres deep in the coastal sea. Due to the strong movement of the sand due to the waves, the sandbanks are often plant-free or very sparsely populated, mainly with vascular plants and charophytes. In addition to the shoals made up of only sand, there are mixed bottoms with different compositions (such as a mixture of sand, gravel, and rocks), depending on the bedrock of the area.
Extensive shallow water areas with sandy bottoms are characteristic of the coastal sea of Western Estonia.