There is little knowledge of movement patterns of Mulloway (Argyrosomus japonicas) within, entering or exiting estuaries. Understanding the movements of fish in relation to changes in the environment is a critical first step in managing estuarine ecosystems to support fish and ultimately forms the basis for future research programs on biodiversity-habitat linkages such as spawning and recruitment. Twenty-eight Mulloway were acoustically tagged within the Glenelg River estuary in South-west Victoria and were tracked via twenty receivers placed throughout the estuary. Estuarine attributes such as salinity, freshwater flows and mouth condition (open or closed) were also measured so that fish movements could be examined with respect to these parameters. Twenty-two of the tagged fish provided movement data. Increased flow discharge triggered exiting the system or movements towards the river mouth. The period from November to January was a “hot” period for Mulloway exiting the estuary, with exiting also correlated with days when flow was higher. Both season and flow conditions were more variable when Mulloway re-entered the system with no specific driver evident. Four Mulloway exited the Glenelg estuary and moved to the Murray Mouth (approx. 400 kilometres away), with two of these subsequently returning to the Glenelg estuary. The extreme angling pressure on Mulloway within the Glenelg estuary is also highlighted. Fifteen of the 22 (68%) tagged Mulloway were captured by recreational anglers, with only one of these fish being released. This data contrasts with the previously documented higher release rates of Mulloway within the Glenelg estuary.