Climate change is one of the most significant drivers of ecological change in coastal marine regions, with rising sea surface temperatures, ocean acidification and marine heatwaves altering coastal conditions and influencing the survival and distribution of marine organisms. Consequently, tropical fishes are increasingly occurring in temperate ecosystems beyond their historical ranges. Rocky headlands are prominent coastal landforms bordered by intertidal and subtidal rocky reefs that provide structurally complex habitat supporting macroalgae and corals, and may provide food resources, shelter and suitable breeding habitat for tropical reef species. In this study, we sampled twenty sites (across ~1400 km of coastline) using diver operated video systems to quantify the abundance, richness and distribution of tropical fish species along the Australian east coast. We found that complex, well connected, structured habitats promoted tropical species abundance and richness, with highest abundance and biodiversity occurring in the northern subtropical regions with evidence of range expansions poleward into the southern temperate ecosystems. These results further indicate that tropical species rely on well-connected reefs as range expansion habitat to facilitate their climate induced migrations. This habitat identification allows managers to anticipate and plan for future migrations into temperate ecosystems yet to be reached.