Merzouga is a long way from anywhere. The nearest airport is at Errachidia (ERH), about 150 kilometres north, which has connections to Casablanca; from there it is two hours by road. The more commonly used airports are at Ouarzazate (WAZ, about 320 kilometres west) or Fes (FEZ, about 390 kilometres north).
The classic approach by road is the southern Morocco loop: Marrakech south over the Tizi n'Tichka pass to Ouarzazate, then east through the Dadès Gorge and Tinerhir (for the Todra Gorge), then on to Erfoud and Rissani before reaching Merzouga. This drive from Marrakech takes 8–10 hours without stops, and most travelers break it into two days. From Fes via Ifrane and Midelt is an alternative northern route, equally scenic, taking around 7–8 hours.
Buses (CTM and other companies) run from Marrakech, Fes, and Casablanca to Rissani, from which shared taxis cover the 25 kilometres to Merzouga. The journey is long and the connections are not always reliable. Most travelers on a tight schedule hire a car or book a guided tour for the southern loop.