This paper reports on four species of the genus Halacarus Gosse, 1855, collected from Izmir and Antalya in the eastern Mediterranean Sea, Türkiye. Two species, Halacarus elifae sp. nov. and Halacarus ercani sp. nov., are newly described, while two others, H. bisulcus Viets, 1927, and H. subtilis Viets, 1940, are reported from the eastern Mediterranean Sea for the first time. Detailed descriptions and illustrations of these species are provided.