Aim Strict public health measures during the COVID‐19 pandemic led to less support for infants and their parents. We aimed to characterise the frequency and nature of infant admissions to the Royal Children's Hospital (RCH), Melbourne in 2020, compared to the previous year. Methods A retrospective review of medical records identified infants ≤3 months admitted to the general medicine unit, RCH from March to September in 2019 and 2020. Diagnoses potentially related to the impact of public health measures and reduced family and community supports were identified and compared to all infant diagnoses across both years. Clinical characteristics and need for referral for additional supports or mental health services were also ascertained. Results There were fewer admissions for infants ≤3 months in 2020 (n = 411) compared to 2019 (n = 678), with a threefold increase in admissions with a primary or secondary diagnosis of feeding difficulties, growth disturbance, infant irritability or maternal mental health concerns (191/411; 46% vs. 97/678; 14%). There were more infants of first‐time parents (112/191; 59% vs. 44/97; 45%) and a reduction in the number of admissions due to infection (145/411; 35%; vs. 467/678; 69%). Conclusion During the COVID‐19 pandemic, there was a threefold increase in admissions for infants ≤3 months due to poor growth, feeding difficulties, irritability and maternal mental health concerns in 2020 compared to 2019. These findings may inform future pandemic planning and policy development to ensure maintenance of community supports such as maternal child health nurse (MCHN) service delivery for young infants.