Elle sera la première des quatre nouvelles lignes du Grand Paris Express à être inaugurée, avant les lignes 15, 16 et 17. Initially scheduled for October 1, 2026, the opening of the first section of line 18 will ultimately not take place until December 2026. So by the end of the year, passengers will be able to travel between the Massy–Palaiseau and Christ de Saclay stations in Essonne. Line 18, the first entirely new metro line in Île-de-France in thirty years, is thus expected to ease the daily lives of many students, researchers, and workers who live, study, or work nearby.