Floodplain wetlands support high biodiversity, including mosaics of vegetation which reflect variable river flows and consequent flooding regimes, characterised by unique variations in extent, duration, frequency and dry time between floods. Environmental water is used to sustain ecological structure and function of floodplain wetlands, and to restore components affected by altered flow regimes. Floodplain vegetation is often the target for environmental water but with relatively little information on key components of the inundation regime over large spatial and long temporal scales. Few studies have quantified inundation regimes required for heterogeneous wetland vegetation types of large floodplains at the landscape. Using novel methods, we evaluated how the inundation regime after the breaking of the Millennium Drought, influenced the dynamics of broad vegetation states of the Macquarie Marshes in the Murray-Darling Basin, Australia. We used multi-temporal inundation maps, classified from the 25 year Landsat archive, to measure extent, duration, frequency and time since last flood, over short-term (5 year) intervals and long-term (20 year) intervals. Using spatial analyses of vegetation distributions from two dates (2008 and 2013) we mapped areas of vegetation change and no change and linked these responses to inundation patterns. Understanding these linkages is critical for evaluating the inundation outcomes of environmental flow management over long-term inundation regime scales.