Common carp (Cyprinus carpio L.), one of the world’s most invasive fish species, are a major threat to wetland and waterway health throughout Australasia and North America.  In a study of pest-fish vagility and vulnerability, the annual dispersal probabilities and propensity to revisit spawning or wintering areas was investigated in adult carp from 2007 to 2011. Carp were tagged and released in multiple groups and locations in the Murray and Darling rivers, Australia. Movements were monitored over four years using an array of acoustic data-logging receivers, PIT tag detecting data loggers and angler recaptures around the Murray–Darling river system (MDB). The study period included low and high-flow periods. River level and temperature were evaluated as environmental triggers for carp dispersal using general linear modelling. A significant proportion (33% ± 9.7%) of tagged adult carp dispersed into tributaries. Mean annual dispersal probabilities ranged from 0.04 to 0.51. Carp migration was partial and nomadic and few showed repeated migrations. The influence of river level and temperature on dispersal varied by release-location. Less than 4% of tagged carp were detected at any fishway along the Murray River equipped with PIT tag detectors. Migration characteristics of carp suggest low population-vulnerability to control by point-source removal, reinforcing the need for broad scale alternative biological controls that can be simultaneously deployed in multiple locations throughout the MDB.