Investigating the phenology of rubber trees (Hevea brasiliensis), a widely cultivated crop in tropical regions exhibiting distinct phenological patterns, is crucial for optimizing plantation management, enhancing production efficiency, and understanding the implications of global climatic change on tropical vegetation dynamics. The purpose of this study is to explores the spatiotemporal variation characteristics and driving factors of rubber phenology over the past two decades on Hainan Island, China’s second-largest rubber plantation base. We applied by integrating multi-source remote sensing imagery processed through the Google Earth Engine (GEE) cloud platform with various analytical methods including the seasonal amplitude method, Savitzky-Golay (S-G) filtering technique, partial correlation analysis, Sen’s slope, and Mann-Kendal test. The results showed that rubber phenology exhibited significant interannual trends and spatial heterogeneity. Specifically, the start of the growing season (SOS) mainly occurred from early to late March (day of year, DOY 60-81), with a trend of advancing by 1.1 days per decade. The end of the growing season (EOS) mostly occurred from late January to early February (DOY 392-406 counted from the previous year), delaying by 3.7 days per decade. The length of the growing season (LOS) lasted 10 to 11 months. Precipitation and topography significantly influenced rubber phenology, with SOS advancing as slope increased and elevation decreased, and increased precipitation accelerating both SOS and EOS at a rate of 1.00 day per 100 mm. Pre-seasonal climatic factors, particularly temperature in February and precipitation in February and March for SOS, and precipitation in January and temperature in February for EOS, were closely related to phenological changes. These findings elucidate the spatiotemporal patterns and underlying drivers of rubber tree phenological changes, offering valuable insights for optimizing rubber plantation management and informing tropical vegetation conservation efforts. Future research should prioritize investigating the impact of global climate change on rubber phenology and developing adaptive strategies to ensure sustainable development in tropical regions.