This case study shows that NDT is critical for coastal bridge durability. Even epoxy-coated rebars in a flyover bridge showed early corrosion from chloride exposure. Using rebar mapping, ultrasonic testing, and corrosion measurements, hidden risks were identified. Targeted retrofitting with corrosion inhibitors, fiber-reinforced polymers, and protective measures was recommended to extend service life, highlighting the importance of data-driven maintenance beyond coatings.