Arenicolids are found worldwide, mostly living in burrows in sandy substrates.

[1] The arenicolids are characterised by an elongated cylindrical body separated into two or three distinct regions.

The notopodia are bluntly truncate and the neuropodia are elongated tori forming long transverse welts in some of the setigers.

The notosetae have either a capillary function or act as limbs and the neurosetae are rostrate hooks.

Their tough cuticle and their distinct branchial region with strongly tufted branchiae are characteristic.