Stress corrosion cracking (SCC) of prestressing steel represents a critical threat to the long-term safety and serviceability of aging bridge infrastructure. This phenomenon occurs within the cross-section and leads to the initiation and propagation of cracks, ultimately causing the rupture of the prestressing wires, which may ultimately result in sudden bridge failure. This underscores the need for reliable monitoring solutions. Traditional non-destructive testing techniques, while valuable, often lack high-resolution capabilities. In contrast, Distributed Fiber Optic Sensing (DFOS) has emerged as a transformative approach, offering high-resolution, continuous monitoring of strain distribution and crack development in concrete structures. This study demonstrates the practical application of DFOS technology for detecting and quantifying crack propagation in operational bridge structures affected by the risk of active SCC. By considering field investigations on four infrastructure projects the research evaluates DFOS performance for structures vulnerable to SCC. The paper demonstrates the technology’s capability to monitor crack dynamics under operational conditions as anomalies in the crack pattern may indicate early symptoms of structural damage caused by SCC. By bridging knowledge gaps in the application of DFOS for infrastructure safety, the study advances the role of fiber optic sensing in addressing SCC challenges, ultimately contributing to the development of more resilient and sustainable bridge monitoring systems.