This research investigates the effects of transient sea levels and aquifer heterogeneity on groundwater flow and solute transport in coastal aquifers through simulations. Using FEFLOW, a finite-element groundwater flow and solute transport model, we conducted 2D simulations, a 200 [m] length over 20 [m] depth simulation, in a Monte Carlo work frame to analyze groundwater flow and salt transport under tidal sea-level fluctuations and changing heterogeneity properties. We used object-based modeling, as well as geostatistical realizations utilizing the sequential indicator simulation (SISIM) algorithm through the Stanford Geostatistical Modeling Software (SGeMS) program. Our preliminary results reveal transient responses in groundwater flow paths to tidal changes, showing areas of preferred flow, along with an increase in the size of the saltwater transition zone, compared to equivalent homogeneous models. In addition, we see a decrease in overall groundwater circulation volumes based on heterogeneity at the tidal zone boundary facies distribution. By comparing heterogeneous and homogeneous models, we assess the effects of different lithological connectivity measures on flow patterns, volumes and solute transport, such as an increase in the fresh saline intertidal zone volume in heterogeneous simulations compared to homogeneous ones, with the greatest difference being between high connectivity steady state and transient simulations. The results provide insight into how heterogeneity affects circulation volumes and salinity distribution, offering information for future coastal aquifer management.