It will be the first of four new Grand Paris Express lines to be inaugurated, ahead of lines 15, 16 and 17. Scheduled initially for 1 October 2026, the opening of the first stretch of Line 18 is now set for 30 November. From that date, passengers will be able to travel between 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 expected to ease the daily lives of the many students, researchers and workers who live, study or commute nearby.