Given their amphidromous behaviour and the use of their skin as a transport epithelium inanga are an interesting model species in which to investigate the effects of salinity on key physiological processes. The aims of the present study were to: 1) characterise the steady-state physiology of inanga after acclimation to different salinities; 2) evaluate their energy expenditures at different salinities; and 3) explore potential salinity-induced changes in the routes (branchial or extra-branchial) used for oxygen uptake and ammonia excretion. It was hypothesised that inanga acclimated to salinities closest to their isosmotic point would display lowest energy costs. In addition, it was proposed that the ability of inanga to utilise the skin as a transport surface would eliminate any evidence of osmorespiratory compromise in this species.