Mangroves reach maximum height when substrate conditions are optimal for extended periods, with growth influenced by a range of edaphic factors and modified by climatic and geomorphological processes. Abrupt transitions in mangrove heights across tidal gradients create a ‘wall-like’ feature, known as a ‘height discontinuity’. This study uses remote sensing to identify height discontinuities across Australia, the species responsible and potential causes. The most notable height discontinuities were found at West Alligator, Leichhardt, Starcke and Port Douglas Rivers, where tall mangrove zones dominated by Rhizophora were located at the highest elevations of the prograding front and tree heights decreased sharply by ~15 m at the landward margin. Shorter landward forests, dominated by Avicennia and Ceriops, were at the highest intertidal positions. Progradation occurred at some sites seaward of the height discontinuity. Analyses of NDVI revealed highest NDVI in tall Rhizophora zones. Dead Rhizophora or sparse mangroves were observed, based on low NDVI, at the landward margin of the height discontinuity. Height discontinuities may develop as mangrove shorelines prograde, with climatic and tidal variability influencing dieback and condition. Understanding the environmental conditions supporting growth of tall mangroves and their changing condition will underpin confidence in carbon markets, based on above-ground biomass.