High pathogenicity avian influenza (HPAI H5N1) has shifted from a predicted threat to an active driver of change in Antarctic and sub-Antarctic wildlife. Since its first detection in the Southern Ocean, collaborative field surveillance has revealed widespread but highly uneven impacts across seabirds and marine mammals. Here, we synthesise insights from integrated HPAI surveillance in the South Atlantic sector, including South Georgia, the Falkland Islands/Islas Malvinas and the Antarctic Peninsula. Combining field sampling, viral sequencing, serology, mortality observations and ecological context, we show how wildlife-focused fieldwork can reveal patterns invisible to opportunistic detection alone, including strong variation in exposure among host groups, evidence for local persistence or repeated introductions at different sites, and candidate ecological pathways for transmission. These findings demonstrate that Antarctic disease surveillance must move beyond reactive, single-site responses toward coordinated, multi-species and multi-season observing systems. We use HPAI as a case study to argue for embedding wildlife disease metrics within the Global Ocean Observing System, including development of an Essential Ocean Variable. Such an approach would improve outbreak and biosecurity preparedness, data sharing and evidence-based conservation responses in a rapidly changing Antarctic region.