The Southern Ocean is home to a multitude of long-lived wildlife species, many of which have been subject to human exploitation. The large-scale exploitation of whale populations in the whaling era led to the near extirpation of large whales across the globe. There is large uncertainty around whether present-day conditions are adequate to support full recovery of pre-whaling population sizes, and the potential effects climate change and other anthropogenic stressors, raise further concerns. Southern right whales (Eubalaena australis, SRW) are a migrating baleen whale species heavily targeted by whaling, leaving only few hundred individuals left across the Southern hemisphere in the 1900s. Population growth in this species is relatively slow, due to the species’ multi-year reproduction cycle. In Australian waters, the species was considered virtually extinct until increasing numbers of occasional occurrences in the 1970s, whereafter the population experienced a period of slow, but steady growth. Using 50 years of systematic aerial survey data, we assessed the recovery trajectory of this population. Our study reveals that whilst the present population size resides far below pre-whaling levels (8-26% of pre-whaling abundance estimates), annual calf production has started declining since 2016, likely linked to a lengthening of female’s reproduction cycle. Moreover, annual coastal abundances of unaccompanied individuals have plummeted, showing a 74% decline since 2011. Our results signal the end of an era of this population's recovery, highlighting that an initial period of steady recovery does not guarantee successful re-establishment of previous abundance levels. We discuss various potential underlying drivers of these marked population-level trends, and identified the knowledge gaps that hamper our understanding of the factors that may be affecting the further recovery of SRWs.