Abstract: Reclaimed-land airports significantly drive economic development in coastal regions, yet they frequently face land subsidence issues, which are critical to operational safety. Accurately predicting subsidence trends is essential for the long-term maintenance of these airports. This study examines Xiamen Xiang’an Airport, utilizing Sentinel-1A data from January 2018 to October 2023, and applies SBAS-InSAR technology to retrieve subsidence data. The subsidence pattern aligns well with Terzaghi’s one-dimensional consolidation theory, enabling long-term predictions through mathematical empirical models. Among four classic models—hyperbolic, exponential, Asaoka, and grey system GM(1,1)—the Asaoka method demonstrated the highest fitting accuracy for predicting long-term trends. Findings indicate a maximum subsidence rate of −51.89 mm/a in the reclaimed area of Xiang’an Airport. Under current load conditions, subsidence in the coastal runway area, part of the third reclamation stage, is projected to persist until 2038, potentially reaching a maximum of −412.98 mm. It is advised to implement artificial interventions during construction and enhance monitoring efforts.