Per- and polyfluoroalkyl substances (PFAS) have gotten global attention as a priority contaminant. Estuarine systems, which connect terrestrial and marine environments, are vital for transporting contaminants through complex hydrodynamic and biogeochemical processes. However, current understanding remains limited regarding PFAS transport mechanisms in the land-sea interface, particularly lacking systematic comparative studies under varying hydrodynamic regimes and industrial structures. This investigation systematically examined the contamination characteristics and land-sea transport processes of traditional and emerging PFAS in three subtropical estuarine systems in China: the medium-small Jiulong River Estuary, the large semi-enclosed Pearl River Estuary, and the large open-type Yangtze River Estuary. PFAS from the Jiulong River Estuary showing the highest concentrations ( 0.87-211.55 ng L^-1, mean 67.10 ng L^-1), exceeding those in the Pearl River (1.97-104.98 ng L^-1, mean 25.38 ng L^-1) and Yangtze River (3.62-69.89 ng L^-1, mean 29.81 ng L^-1) estuaries. By integrating hydrological parameters, particle size distribution, elemental composition, and organic/elemental carbon (OC/EC) analysis, this study elucidated key factors governing PFAS transport dynamics in estuarine-coastal environments. The findings provide theoretical foundations and practical insights for developing refined pollution control and management policies.