There are a lot of companies doing this route, usually they leave in the morning when full from Sebkha district near Cordon Bleu Hotel.
First I went to negotiate price and book for the next day whithout paying. In the morning we went wit luggage and after we were all sent in the car we payed the company and left to the journey.
It was a normal 5 seat car, they put 5 passengers behind and 2 in the front. We payed 800 Ouguiya and the driver promised me that on the other side would be another car waiting for us to bring us to St Louis, all included in the price.
Other companies were charging 700 to the border and 1000 to St Louis (mini vans and micro buses). All the companies are in the same district and is not the same place where you take the buses via Rosso border.
I arrived in station 8:30 and it left 9:15 when full. We passed in around 5 police checks but no one asked for passport or fiche (as really common in the road to Atar), I believe the driver was well known, he always left the car and maybe give some little money. Around 1 pm we arrived in the border.
The driver was very helpful, he took our passport to the officers and they asked our last fiche for Mauritania, this took 10 minutes. They didn’t stamped our passports. Meanwhile 2 guys with a wheel car were carrying all our bags to the Senegalese side. We went to another booth that go out fingerprints, asked where we were staying and our jobs. 5 minutes, and on this place we were stamped out (not stamped in yet).
Our driver walked us to Senegalese side and put us beside another car to st Louis and near our bags and told us to wait, he kept our passports. Took about 30 minutes, and he came back with passports stamped in. I didn’t understood why took so long, maybe he had to pay more bribes, who knows. On this 30 minutes only 2 men came to offer exchange with bad rates and sim-cards, not like Rosso reports of tons of touts.
We were put in the car with same people but another diver and dropped wherever we asked in St Louis. We haven’t paid extra for the second car, as they promised. We arrived around 2:30pm