Ocean warming is reshaping marine populations across all life stages, but how connectivity processes shape the response of larval supply to warming regions remains difficult to resolve. We tested this in the data-rich southern rock lobster (Jasus edwardsii), with pelagic larval drift of around two years across a range spanning half a continent. Using a 31-year (1993–2023) particle-tracking model forced by an ocean reanalysis (BRAN2020), we found that ocean warming produced opposing larval supply trends across the range over time. Settlement declined at the warm edge as heat-related mortality increased, but rose at the cold edge as cold-related mortality eased. We developed a decomposition technique that partitioned larval thermal exposure into local warming and transport-driven thermal components. Local warming dominated at six of seven regions and contributed, on average, seven times more than transport to the warming experienced by larvae. This technique offers a general way to test whether larvae are being advected through warmer areas or if the pathways themselves are warming. For long-duration dispersers, ocean warming may outweigh transport pathways in driving opposing settlement trends at species range edges.