Details of individual southern rock lobster (Jasus edwardsii) samples and their respective delta carbon-13 (δC13) and delta nitrogen-15 (δN15) values from a captive feeding experiment (Smith et al., 2023). Lobsters were collected by divers as puerulus larvae at Iron Pot, Tasmania at 9 m depth and raised in circular flow through tanks at the Institute for Marine and Antarctic Studies, Taroona, Tasmania. Samples include those from dorsal muscle, dorsal carapace, leg muscle and leg exoskeleton. Lobsters were in three diet treatments and were sampled at 0, 4, 8, 12, and 18 months after a diet change. The experiment took place in Hobart, Tasmania, Australia between June 2020 and December 2021. The experiment was used to determine trophic discrimination factors for stable isotope analysis of lobsters, and investigate variability of stable isotope signatures over time. Isotope values were analysed using flash combustion isotope ratio mass spectrometry.