Aims There has been a recent increase in the incidence of paediatric acute mastoiditis (AM). Management includes medical and surgical interventions, and there has been a global trend towards managing paediatric AM more conservatively. The aim of this study was to evaluate the contemporary management of paediatric AM in Aotearoa New Zealand. Methodology A retrospective observational study was conducted, including patients aged <18 years with an ICD-10 diagnosis of AM, treated in one of five tertiary hospitals across Aotearoa New Zealand between 2014 and 2022. Results There were 212 cases of AM during the study period. There were 104 cases (50%) of uncomplicated AM and 108 cases (51%) of complicated AM. Complications included 75 cases (35%) of sub-periosteal abscess, 18 cases (9%) of intra-cranial infection, 21 cases (10%) of venous sinus thrombosis and 6 cases (3%) of petrous apicitis. During the study period the proportion of all AM cases managed with mastoidectomy increased from 13% in 2014 to 36% in 2022 (p = 0.05). 94 (90%) cases of uncomplicated AM were managed with medical therapy alone or limited surgical intervention with a low rate of return to theatre (2%). 102 (94%) cases of complicated AM were managed surgically with at least ventilation tube insertion. A subgroup of these cases included 75 patients with subperiosteal abscess, 42 of whom were managed with ventilation tube and incision and drainage or aspiration, with a low number requiring further surgical intervention (5%). Conclusions Our results support the management of uncomplicated AM with either medical therapy alone or limited surgical intervention, and the management of complicated AM with subperiosteal abscess with limited surgical intervention. This local data can be used to develop recommendations in the management of paediatric acute mastoiditis in Aotearoa New Zealand.