The short answer
Not realistically. The big Sahara dunes at Merzouga are 560 km from Marrakech, about 8 hours 30 minutes of driving each way, so they need at least two days and ideally three. For a desert evening in a single day, the Agafay stone desert is about 30 km away, without dunes but with camels, quads and sunset dinners.
In more detail
Any tour that promises the Sahara and back in a day means many hours in a car and very little desert. The route crosses the Tizi n'Tichka pass, Ouarzazate and the gorges, and it is best split with a night on the way.
A sensible short version is two or three days: over the Atlas to Aït Ben Haddou, through the Dadès or Todra gorges, a night in a desert camp at Merzouga, then back. Zagora and Erg Chigaga are the other desert options, also a multi-day trip.
If you only have a day, choose a day trip that does one thing well: Aït Ben Haddou for the kasbah road, or Agafay for an evening in the desert landscape.
Good to know
- Do not drive the Sahara roads after dark.
- Book desert camps early for the winter holidays.
- Agafay is a good opener even if you plan the Sahara later.