Harpactocarcinus yozgatensis has a densely punctate carapace which is approximately 0.8x as long as it is wide and features four frontal spines and ten to thirteen small, anterolateral ones.^[1] Like other species of Harpactocarcinus, it exhibits moderate heterochely, having a larger right cheliped than its left.^[1] It has very deep orbits which can – in conjunction with its small chelae – distinguish it from other species of Harpactocarcinus.^[1]

The excellent preservation of H. yozgatensis presented the first robust description of the abdomen of Harpactocarcinus.^[1] The male abdomen's segments are narrow, whereas the female's are convex and broad.^[1] The first and second segments of the abdomen are fused in both sexes, and in males, the third through fifth segments are also fused.^[1]