This study presents the results of a comprehensive investigation of the macrofungal diversity in South Korea conducted between 2022 and 2025. Our approach has integrated detailed morphological observations with molecular analyses of large subunit (LSU) sequences. In the present study, we have identified four species, Retiboletus fuscus, R. sinensis, R. sinogriseus, and R. zhangfeii —that were previously unrecorded in South Korea. These findings significantly enhance the current understanding of fungal biodiversity within this region and also provide essential foundational data for advancing local and international mycological research.