Mangrove forests are located along (sub)tropical shorelines and can contribute to flood risk reduction and shoreline stabilization. Evidence of the wave-attenuating function of mangroves is increasing, but knowledge gaps persist regarding the critical conditions to mangrove forest development. The implementation of mangroves in coastal engineering practice also requires a firm understanding of these critical conditions (Gijsman et al., 2021). Conditions and thresholds for mangrove seedling establishment are key in the long-term development and survival of mangroves. Compared to mature mangrove trees, establishing young mangrove seedlings are much more vulnerable to daily to seasonal fluctuations in hydrodynamics and bed level dynamics (Balke et al., 2015). This study aims to develop a mangrove seedling establishment model to study the biophysical interactions and feedbacks between mangrove forests, tides, waves, sediment dynamics and seedlings. Combining field observations and numerical modelling, we will assess the critical conditions for mangrove seedling establishment on a daily to seasonal timescale.