Bathyomphalus contortus is a species of small air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Planorbidae, the ram's horn snails and their allies.

It occurs in countries and islands including: The 1-2 × 3-6 mm shell has up to 7-8 densely coiled and rounded whorls with deep suture.

The animal is blackish dark red, tentacles very long, eyes small and black.

Bathyomphalus contortus is tolerant of acidic conditions as is Radix balthica.

In Ireland it is often the only species present in pools or drains in and around raised bogs.