The rocky shores of New Zealand (NZ) and Australia provide many interesting comparisons in their intertidal species and structuring processes. Both countries are in the biogeographic realm of temperate Australasia and share many common species and closely related taxa. Here we review similarities and contrasts in communities and structuring processes, especially involving grazing invertebrates and macroalgae. We consider the similarity of the structure of intertidal shores of NZ and south-eastern Australia, a suite of important trophic interactions within and between regions, the utility of local-scale experiments in understanding large-scale processes and how we might better plan for and manage our coasts. The major comparisons are between warm-temperate areas of northern NZ and New South Wales, and the cooler areas of southern NZ and south-eastern Australia. In the quest for ‘ecosystem’-level understanding, which perforce involves large-scale events, there is an increasing tendency to minimise or ignore the hard-won insights gained from well-structured experiments across multiple sites. Because all large-scale effects must be manifested at local sites, it is incumbent on us to determine what scales up or down, and the caveats that make comparisons across biogeographic regions challenging. Here, we discuss these issues using austral shores as models.