Sesuvium portulacastrum, commonly known as sea purslane or shoreline purslane, is a trailing herb from the Aizoaceae family. It is a halophytic (salt-tolerant) plant species that thrives in coastal environments worldwide. This review deals with the biological characteristics and ecological significance of S. portulacastrum, emphasizing its role as a pioneer species in subtropical and tropical sandy beach environments. Sesuvium portulacastrum plays a critical role in coastal ecosystems, particularly on sandy beaches. Its stoloniferous, mat-forming growth habit is instrumental in promoting the formation of embryonic dunes. These dunes, often aligned parallel to the shoreline, are essential for coastal stabilization and protection. The dense colonies of S. portulacastrum act as natural barriers, effectively intercepting and retaining sand transported by wind and water. A key factor in the success of S. portulacastrum as a colonizing species is its ability to propagate through vegetative fragments. These fragments exhibit remarkable tolerance to salt water, allowing them to survive and establish new colonies in diverse coastal environments. The species has dispersed to various global locations primarily through drifting sea segments, showcasing its resilience and adaptability. Sesuvium portulacastrum is a vital pioneer species on subtropical and tropical beaches, contributing significantly to coastal dune formation and stabilization. Its propagation through vegetative fragments and salt tolerance underpins its widespread distribution and ecological success. These characteristics make S. portulacastrum a potential species for biosaline agriculture.