Significance Monitoring neuronal activity with cell specificity in freely behaving animal models can yield insights into underpinning operating mechanisms of the brain. Dynamics of genetically targeted neuronal populations can be recorded through calcium indicators; however, current tools for such measurements are only available with tethers or large and heavy externalized head stages, with potential to influence behaviors of the test subjects and to limit experimental paradigms to simple two-dimensional arenas. Here, we introduce highly miniaturized, wireless, battery-free, and subdermally implantable photometry systems that bypass these limitations to enable chronic recording of neural dynamics in ethologically relevant environments with no impact on test subject behavior. This technology has potential for broad utility in neuroscience research and can enable fundamentally new experiments in neuronal dynamics and simultaneous behavior studies.