Positron emission tomography (PET) plays key roles in drug discovery and development, as well as medical imaging. However, there is a dearth of efficient and simple radiolabeling methods for aromatic C-H bonds, which limits advancements in PET radiotracer development. Here, we disclose a mild method for the fluorine-18 (F-18)-fluorination of aromatic C-H bonds by an [F-18]F- salt via organic photoredox catalysis under blue light illumination. This strategy was applied to the synthesis of a wide range of F-18-labeled arenes and heteroaromatics, including pharmaceutical compounds. These products can serve as diagnostic agents or provide key information about the in vivo fate of the labeled substrates, as showcased in preliminary tracer studies in mice.