The territory of Strandzha Nature Park falls within the Mediterranean soil area of Europe, characterised by wetter soils in comparison to the rest of Southern Europe. There are seven soil types in the park under the World Reference Base for Soil Resources soil classification — Fluvisols (4% of the park's area), Leptosols (10%), Cambisols (4%), Luvisols (46%), Planosols (20%), Alisols (11%) and Nitisols (5%). Strandzha is the only place in Bulgaria where Alisoils are found and the only place in Europe with Nitisols.