Decision-making for infants born at 23-25 weeks involves counselling parents about survival and major disability risks. Accurate information is needed for parents to make informed decisions about their baby's care. To determine if perinatal clinicians had accurate perceptions of outcomes of infants born at 23-25 weeks' gestation, and if accuracy had changed over a decade. A web-based survey was sent to midwives, nurses, neonatologists, and obstetricians working in tertiary and non-tertiary hospitals, and the neonatal retrieval service in the state of Victoria in 2020. A similar survey had been completed in 2010. Clinicians' estimates of survival and major neurodevelopmental disability rates were compared with true rates for actively managed infants overall, and by infant birthplace and gestational age, and professional workplace and discipline. Accuracy of outcomes was compared between eras. Overall, 165 surveys were received. Participants underestimated survival (absolute mean difference [%] -14.4%; [95% confidence interval (CI) -16.6 to -12.3]; P < 0.001) and overestimated major disability (absolute mean difference 32.7%; [95% CI 29.7 to 35.8]; P < 0.001) rates overall, and at each week of gestation, and were worse for outborn compared with inborn infants. Perceptions of clinicians in tertiary centres were similar to those of non-tertiary clinicians. Nurses/midwives were more pessimistic, and paediatricians were more optimistic. Clinicians' perceptions of outcome were less accurate in 2020 than in 2010. Most perinatal clinicians underestimate survival and overestimate major disability of infants born at 23-25 weeks' gestation, which may translate into overly pessimistic counselling of parents.