This study investigates the bryophyte biodiversity of Harmankaya Waterfalls Nature Park in Zonguldak, Türkiye, an area with critical biological significance for hornworts and other bryophyte species. Fieldwork conducted in 2023-2024 documented bryophyte diversity across three environmental zones based on substrate-water interaction levels. A total of 164 bryophyte taxa were identified, including 3 hornwort, 39 liverwort, and 122 moss taxa, with 32 new records for the Zonguldak bryoflora. Biodiversity was assessed using the Shannon diversity index, revealing that Zone II, characterized by a mix of aquatic, semi-aquatic, and terrestrial taxa, exhibited the highest diversity. This study highlights the need for enhanced conservation strategies for Harmankaya due to increasing anthropogenic pressures from recreational activities, underscoring the importance of reevaluating its protected status.