Background: Mother-baby units are innovative and important models of care that allow inpatient treatment of postpartum maternal mental disorders whilst preserving and promoting the attachment relationship with their young infants. Objectives: To report data across five public mother-baby units in Australia in order to explore similarities and distinguishing features of each model. Method: Each unit also provided 12 months of data on key characteristics of their unit. Results: Despite the geographic differences, the diagnostic profiling, length of stay, and child protection involvement were similar across the units. Conclusions: Acute care for perinatal mental illness offered in public mother-baby units in Australia shows consistency across units, raising concerns for where such treatment is unavailable.