Changes in coastal morphology have significant implications for the sustainability of communities, infrastructure, and ecosystems. The lack of high-spatial and -temporal resolution data makes coastal monitoring challenging. Optical remote sensing has proven to be an effective tool for studying large areas, providing consistent and comparable data. This study analyzes morphological changes in the Pichilemu Bay, O'Higgins region, Chile, using satellite images from Landsat (5, 7, 8, 9) and Sentinel-2 between 1985 and 2024. The objective is to understand the relationship between natural drivers and shoreline fluctuations, with an emphasis on the effects of the 2010 earthquake, which established a new baseline for the coastline. The bay was divided into three sectors based on wave influence to analyze coastal dynamics and morphosedimentary patterns. The methodology included the following: a) massive extraction of shorelines; b) wave analysis using ERA 5 simulations; c) erosion rate calculations and spatiotemporal analysis of beach width; and d) sediment analysis across three beach profiles. The results reveal significant erosion rates of up to -1.17 m/year, exacerbated by extreme events such as storms and ENSO cycles, which alter wave patterns and sediment distribution. Coastal storms are key drivers of the bay's evolution, as they activate transport processes absent under normal conditions, such as increased longshore transport and sediment redistribution toward deeper areas. This impact is particularly evident during multi-year erosive cycles, such as the one recorded between 2012 and 2020, associated with recurring storms and ENSO-driven wave patterns. This spatiotemporal model reconstructs the beach’s evolution and shoreline position, highlighting the influence of disruptive events on its development.