As with most tropical reef systems, coral reefs in the western Indian Ocean are under severe threat from anthropogenic stressors such as climate change. However, not all coral reefs are equally as vulnerable to environmental change, and one parameter that may be important is reef connectivity. Larvae from broadcasting corals can be swept over significant distances through ocean currents, facilitating the exchange of coral larvae between distal reef sites and potentially playing an important role in maintaining reef resilience. To assess the connectivity (including temporal variability and physical oceanographic drivers thereof) of coral reefs across the southwestern Indian Ocean, we have combined high-resolution (2km) multidecadal simulations of ocean currents spanning almost all coral reefs in the region, with a biological particle tracking model. We will compare results from these simulations to estimates of coral population connectivity from coral population genetics across Seychelles to identify keystone reefs for marine spatial planning efforts, and to determine the physical and biological factors controlling reef connectivity in this region.