Boreal forest wetlands are strongly influenced by groundwater dynamics and permafrost processes, yet these interactions are poorly represented in current hydrological and land surface models. We present a modelling framework that explicitly couples groundwater flow with freeze–thaw soil physics to simulate water table dynamics, subsurface connectivity, and wetland extent in boreal landscapes. The approach accounts for freeze–thaw–dependent changes in subsurface transmissivity, active layer depth, and groundwater storage, and links grid-cell mean conditions to subgrid wetland saturation through a topography-based parameterization. Model results are evaluated against observations of water table depth, soil moisture, and soil temperature at a boreal wetland site. Simulations show that groundwater processes control seasonal wetland persistence, while permafrost exerts a dominant influence on runoff partitioning and event-scale hydrological responses. Our results emphasize the importance of representing groundwater–permafrost interactions to improve predictions of boreal wetland hydrology under climate change.