AbstractUV radiation is considered indispensable from the hygienic, medical, aesthetic, and industrial perspectives. Among the various types of UV radiation, UV‐A (with a wavelength of 315–400 nm) has a significant influence because it adversely affects human skin, leading to damage such as blemishes, freckles, and wrinkles. Although various photosensors are developed for monitoring UV‐A radiation in real time, these devices have critical issues, such as inefficient fabrication processes, insufficient photoresponsivity, and incompatibility with long‐term wearable applications. Here, the authors report on a wearable UV‐detecting patch targeted for long‐term use in the medical and clinical fields. A wearable UV sensor is fabricated by integrating optimized InGaN/GaN microphotodetectors (µPDs) in a 3D porous patch. The optical and electrical properties of the device are intensively investigated under various types of optical radiation and input electrical power and show high photoresponsivity (2.82 A W⁻¹) and excellent external quantum efficiency (897.63%). Long‐term real‐time UV radiation monitoring using the wearable µPDs is demonstrated; moreover, the by‐products can be efficiently removed from human skin surfaces.