As ocean warming threatens temperate ecosystems with tropical range shifts, now, more than ever it is important to understand how ecosystem function varies along spatial gradients. Intertidal rock platforms are extensive but understudied marine ecosystems in Western Australia that support high invertebrate species richness. Molluscs are the most abundant and diverse fauna found on rock platforms and play an important role in supporting trophic structure. Knowledge of functional diversity and structure of molluscan assemblages is limited globally and has not been previously documented for intertidal ecosystems in Australia. Our study sampled across a vast geographic extent, spanning 16° of latitude and 39 limestone platforms, capturing the well documented temperate/tropical transition zone found between 22°S - 24°S. A trait database for 228 molluscs species found on rock platforms will be used to show how the trait composition of assemblages change with latitude. Adapted relatedness measures will be used to combine ecological and life history trait information with morphological and occurrence data to investigate the functional diversity, distinctiveness and turnover of assemblages. Investigating the functional compositions of mollusc assemblages will provide insights into key ecological structures and inform how range shifts could affect intertidal communities in the future.