The short answer
A petit taxi is a small city cab for short trips inside one town, and it cannot legally leave the urban area. A grand taxi is a bigger car, in Marrakech often an older cream Mercedes, that runs shared fixed routes between towns and leaves once it is full. You can also pay to charter a whole grand taxi.
In more detail
Petits taxis take up to a few passengers and work like city cabs anywhere, with a meter that should be switched on. Grands taxis work more like a shared minibus. Each seat is sold separately, the car waits at a rank until every seat is taken, then sets off on its usual route.
That makes grands taxis a local, low-cost way to reach places like Asni or the Ourika road, but the timing is loose. Agree the terms before departure, and know that you either wait for the car to fill or pay for all the seats yourself.
For a day trip with stops, a grand taxi is not ideal: the driver follows the route, not your plans. A private driver goes door to door, waits while you walk, and stops where you ask. For long hauls, CTM and Supratours coaches are the comfortable public option.
Good to know
- Ask your riad where the grand taxi rank for your destination is; ranks differ by route.
- Confirm whether the fare is per seat or for the whole car.
- For airport runs with luggage, book a transfer rather than a grand taxi.