The unprecedented climate warming is profoundly altering all aspects of life. Metabolic rate, a key physiological and ecological trait, mediates the effects of climate change, providing significant predictive power for forecasting its impact. Understanding and accurately predicting metabolic responses to changing temperatures is therefore essential for anticipating species’ vulnerabilities, adaptive capacity, and broader ecosystem consequences. This is especially relevant for invertebrate communities, which play critical roles in ecosystem functioning and are particularly sensitive to thermal shifts. The urgency is heightened in the semi-enclosed Adriatic Sea, where pronounced changes in invertebrate populations and community composition have recently been observed. Here, we aimed to assess how the standard metabolic rate (SMR) of invertebrate species in the Adriatic Sea responds to temperature changes and to project its change under various IPCC climate emission scenarios by 2100. We measured the individual SMRs of nine invertebrate species collected from locations spanning the southern to northern Italian coast of the Adriatic Sea, across two acclimation temperature levels. Our findings indicated a shallower-than-expected dependency of SMR on body mass, and on temperature. We further showed that metabolic rates in Adriatic species are projected to increase by ~ 10–30 %, from the most conservative to the most severe climate change scenarios. This finding provides a baseline for understanding elevated minimum energy costs under expected temperature increases, enabling predictions of higher-order, metabolism-related ecological processes