The Gulf of Carpentaria, Coral, Aurafura and Timor seas of the Northern Territory and far North Queensland have unique billfish fisheries with impressive seasonal aggregations occurring during the Austral Spring/build up. Billfish are very difficult to collect movement data on, renowned for shedding tags and the fishery is understudied. No electronic tags have been reported on from central Northern Australia and only a handful of studies from the North-east coast. Between November 2022 and 2024 we deployed 28 PSAT tags on sailfish and two on black marlin to study the influence of the monsoonal wet season on sailfish dispersal patterns and habitat use. We also deployed acoustic V16s on an additional 23 sailfish and three black marlin to compare tagging methods and assess the feasibility of using acoustic telemetry in billfish. Fifteen of the 30 PSAT tags have reported, with deployments ranging from two – 339 days, while five tags are still at liberty. Preliminary analysis of these deployments indicates seasonal changes in diving behaviour and distribution with fish tagged in the gulf of Carpentaria during the Austral Spring dispersing as far as the Banda Sea of Indonesia in Autumn and simultaneously changing their dive profiles. Acoustic telemetry also proved surprisingly effective in sailfish with both internal and external tags registering detections, the longest up to 447 days after tagging. This study has identified previously unobserved migration routes and demonstrates the advancements fishery independent tagging studies can have on our understanding of sailfish dispersal patterns and habitat use.