Worldwide, rock lobsters are considered important predators that control sea urchins. However, it is not known whether the abundant Australian species, the eastern rock lobster (Sagmariasus verreauxi), occupies a similar role. Isotope analysis can be used to investigate lobster diet based on prey assimilation of nitrogen and carbon isotopes. However, since recent work has shown that tissues taken from the leg, antennae or abdomen of lobsters can give different indications of diet, work is now needed to determine whether different body parts and tissue types have different isotopic ratios or whether all body parts provide similar estimates, and can be used interchangably. Understanding this is necessary to prevent erroneous conclusions about lobster food webs being drawn and may offer an opportunity to use novel, non-lethal sampling approaches to investigate diets since lobster appendages might be a suitable substitute for abdomen tissue, which is lethally obtained. We evaluated this by dissecting 30 lobsters and comparing δ13C and δ15N isotope values in antennae, leg and abdomen tissue from the same individuals ranging from 104–137 mm Carapace Length (CL). Our results show that S. verreauxi can now be sampled non-lethally via antennae or leg removal with mathematical corrections applied.