<p>Civil infrastructure, such as bridges, tunnels, and pipelines, spans thousands of miles across many countries and is vital to economic stability and public safety. However, maintaining such large-scale systems presents significant challenges. Conventional Structural Health Monitoring (SHM) relies on visual inspections and specialized equipment, which are often costly and resource intensive, thereby necessitating the need for more scalable and accessible alternatives. In recent years, smartphones have emerged as promising tools for SHM due to their portability, built-in sensors, computing capabilities, and widespread availability. While earlier research focused more on the smartphone application in healthcare and environmental monitoring, recent studies have begun leveraging smartphones to assess infrastructure conditions by collecting, processing, and transmitting data through distributed nodes. With appropriate algorithmic support, such as noise filtering and signal interpretation, smartphone-based monitoring can serve as a viable, lower-cost complement to traditional SHM systems. This review examines the potential of smartphones as low-cost, scalable platforms for SHM, emphasizing how their integration can enhance the accessibility of infrastructure monitoring, particularly in resource-limited regions. Despite remarkable progress in smartphone-sensing applications, challenges remain in ensuring data reliability, sensor synchronization, and cross-device consistency, which constitute key directions for future research. From a sustainability perspective, repurposing smartphones for SHM offers a promising approach to bridging technological and economic disparities in infrastructure maintenance.</p>