Heritiera littoralis is a mangrove-associated plant distinguished by its unique fruit morphology and capability for transoceanic dispersal. Understanding its dispersal routes and population distribution is crucial for addressing ecological issues related to climate change. While drift disseminules are generally known for their buoyancy, this study investigates specific structural traits that enhance their long-distance dispersal efficiency. By integrating morphological and biomechanical analyses, we identified key features that optimize the fruits of H. littoralis as sea-drift propagules: (1) Buoyancy: The overall density is lower than seawater due to numerous air cavities within the fibrous mesocarp. (2) Stability: The seed's position and localized water absorption in the mesocarp stabilize the center of buoyancy, enabling the fruit to ""self-right"" and float upright, resisting rolling in waves. (3) Aerodynamics: The dorsal keel-like ridge acts as a sail, enhancing aerodynamic drag. This allows fruits to exploit both hydrodynamic and wind forces for rapid drift. (4) Durability: Multiple hydrophobic layers, from the exocarp to the seed coat, prevent seawater intrusion, maintaining seed viability during prolonged oceanic transport. Among drift-dispersed species, H. littoralis exhibits superior resistance to seawater and effectively utilizes environmental forces, demonstrating exceptional adaptation for transoceanic dispersal. These findings suggest that H. littoralis can serve as a vital indicator species for assessing the impact of climate change on coastal drift plants.