Obesity is costly, yet there have been few attempts to estimate the actual costs of providing hospital care to the obese inpatient. This study aimed to test the feasibility of measuring obesity-related health care costs and accuracy of coding data for acute inpatients. A prospective observational study was conducted over three weeks in June 2018 in a single orthopaedic ward of a metropolitan tertiary hospital in Queensland, Australia. Demographic data, anthropometric measurements, clinical characteristics, cost of hospital encounter and coding data were collected. Complete demographic, anthropometric and clinical data were collected for all 18 participants. Hospital costing reports and coding data were not available within the study timeframe. Participant recruitment and data collection were resource-intensive, with mobility assistance required to obtain anthropometric measurements in more than half of the participants. Greater staff time and costs were seen in participants with obesity compared to those without obesity (obesity: body mass index ≥ 30), though large standard deviations indicate wide variance. Data collected suggest that obesity-related cost and resource use amongst acute inpatients require further exploration. This study provides recommendations for protocol refinement to improve the accuracy of data collected for future studies measuring the actual cost of providing hospital care to obese inpatients.