Lasius psammophilus is a small brown to dark brown ant which until recently was confused with L. alienus Förster. Seifert (1992) showed that it was a distinct species based on morphological differences coupled with distinctly different habitat preferences. The scapes and tibia have no erect hairs. Workers can be separated from the sibling species L. alienus by the greater number of hairs (2-5) between the propodeal spiracle and the metapleural gland.
It is distributed in England and Wales with a bias towards coastal sites and sandy heaths. Previous confusion with L. alienus means that it is probably currently under-recorded.