A significant increase in forest cover in Europe is possible through the afforestation of post-agricultural lands, a practice widely implemented across the continent. However, this process is strongly constrained by the specific physicochemical conditions and biological impoverishment of such soils, resulting from long-term agricultural use. Research on the structure of soil fauna inhabiting post-agricultural lands has been conducted in Europe by various authors, but only a small number of studies have linked their results with the full spectrum of environmental factors influencing edaphic communities. Moreover, the use of predatory mites from the order Mesostigmata as bioindicators of forest succession on post-agricultural lands remains extremely rare. The present study included even-aged (22, 42, and 62-year-old), single-species stands of Scots pine (Pinus sylvestris L.), sessile oak (Quercus petraea (Matt.) Liebl.), silver birch (Betula pendula Roth.), small-leaved lime (Tilia cordata Mill.), and European beech (Fagus sylvatica L.) established on both post-agricultural and forest soils. For each habitat–stand variant, the soil type, stand taxation parameters, and a wide range of soil physicochemical properties were determined. Over two years (2020–2021), four series of soil samples were collected, with a total of 2,056 samples analyzed. This resulted in data from 21 forest stands and 57 research plots. In total, 8,484 mites belonging to the order Mesostigmata were identified, representing 77 taxa. The results showed that communities of these mites inhabiting post-agricultural soils were poorer in terms of abundance, species richness, and species diversity than those found in forest soils; however, this effect diminished with increasing stand age. The observed differences were influenced, among other factors, by the concentrations of sodium, nitrogen, zinc, and manganese in the soil. Furthermore, the study demonstrated that the influence of tree species on mite communities depends on the land-use history of the site. Therefore, the appropriate selection of tree species composition becomes an important factor in the restoration of post-agricultural soils. Additionally, it was shown that comparisons of the effects of tree species forming stands on post-agricultural lands on the soil fauna inhabiting them should take seasonal variation into account. This is due to the changing influence of particular tree species on forest floor conditions in response to climatic fluctuations throughout the annual cycle.