The invention relates to an extendable device for accessing a vehicle, said vehicle including a housing (3) for storing the device extending below a vehicle access threshold (2) and having a window (4) enabling the extension of the device, wherein said device includes: a mobile ramp (5) capable of translation along an axis A between a stored position in the housing and an extended position； and a mobile flap (8) rotatably moveable about an axis B between a protection position in which the flap closes the window (4) of the housing (3) and an extended position in which the flap defines an inclined plane between the ramp (5) and the access threshold (2). The invention also relates to a platform for accessing a vehicle.
