The short answer
Both work well. Direct ONCF trains take a little under three hours to Casa-Voyageurs and are the simple choice for solo travellers. A private car covers the 240 km on the A7 toll motorway in about 2 hours 45 minutes, door to door, which suits families, heavy luggage or a flight to catch. Coaches are cheaper and slower.
In more detail
The train runs station to station. Marrakech station is in Gueliz, a short taxi from the medina, and in Casablanca you arrive at Casa-Voyageurs, from where you still need a taxi to your hotel. Check times and fares on oncf-voyages.ma and book ahead around holidays.
A private car starts at your riad and ends at your hotel, or at the airport terminal. It is the motorway the whole way, the fastest and smoothest road in the country, so the time is predictable.
CTM and Supratours coaches run between the two cities too. They are comfortable enough, but slower than the train, especially when traffic builds in Casablanca.
Good to know
- Solo or travelling light: the train, booked a day ahead in busy periods.
- A family with luggage, or a flight to catch: a private car.
- Driving yourself: consider returning a hire car before you enter central Casablanca.