Abstract. Three species of ants, Lasius niger, Myrmica rubra and Myrmica scabrinodis, have been recorded in a 20‐year‐old coastal plain on the Dutch Wadden Zee island, Schiermonnikoog. The habitats of these species appeared to be clearly segregated, both horizontally (different parts of the plain) and vertically (along dune slope gradients in the plain). Lasius niger is distributed throughout the plain in sparsely vegetated sand‐dunes and in mounds covered with turf of Festuca rubra ssp. litoralis, but always in areas that are only waterlogged or inundated in winter. Myrmica rubra is limited to Festuca‐turf, occurring in a distinct zone along the bases of small dunes and on isolated mounds. Myrmica scabrinodis only occurs in mounds covered with Festuca‐tutf and rarely in the small dunes. Analysis of soil, vegetation, inundation and salinity of the ground‐water demonstrated that Myrmica scabrinodis is dominant in areas with more silt and salt in the soil, characterized by a vegetation with more typical halophytes, whereas Myrmica rubra occurs most frequently in sandy habitats without much salt stress. The populations of both Myrmica species and Lasius niger do not seem to be affected by inundation during winter. The distribution of the ant species is discussed in relation to data about ants in more stable habitats. In particular, attention is given to the absence, in this coastal plain, of Lasius flavus which is a dominant species in the sand‐dunes and neighbouring parts of the salt‐marsh on Schiermonnikoog.