In the north, it is not a simple line on the map that has to be crossed but a river, the Senegal River. Two crossing points let you reach Mauritania by car, with very different logics: the Rosso ferry or the Diama dam.
Two crossings, two logics
The border with Mauritania runs along the Senegal River for hundreds of kilometres, but two points concentrate most of the road traffic. Rosso, east of Saint-Louis, is the historic crossing: a ferry links the two banks, on the Senegalese side and the Mauritanian side, each bearing the same town name. Diama, closer to Saint-Louis and reached via the Diawling National Park, crosses the river over the anti-salt dam built in the 1980s, a fixed structure that removes the dependence on a ferry timetable.
The choice between the two depends mainly on your starting point and your tolerance for the unexpected: Rosso stays more direct if you come from the east of the country, Diama requires a detour through the reserve but offers a more predictable crossing. If your road trip starts with a rental in Dakar, allow a good day's drive to Saint-Louis before even tackling either crossing.
Rosso, the ferry that does not hurry
- ▸The bridge announced at Rosso is still under construction in 2026: the crossing is still made by ferry, at a frequency that depends on the river level and the crowds.
- ▸Informal approaches from improvised go-betweens are frequent on both sides: it is better to stay polite but firm, and to settle nothing outside the official counters.
- ▸Allow a wide margin on your timing: between the wait for the ferry and the customs formalities on each side, a whole morning can go by.
Diama, the detour that simplifies
Reaching Diama from Saint-Louis means crossing the Diawling National Park, a track passable in the dry season but which can deteriorate after heavy rainy-season downpours. In return, the crossing itself is simpler: no ferry to wait for, a fixed charge for the use of the dam, and a markedly smaller flow of travellers than at Rosso.
These amounts change regularly: treat them as an order of magnitude to prepare your change, not as a fixed rate.
Rental car: the written agreement above all
As with the Gambian border, most Senegalese rental companies exclude leaving the national territory by default from their standard contract. Crossing into Mauritania with a rental car requires a prior written agreement, and often a vehicle transit permit to be drawn up at the border post. Unlike the Gambia, an ECOWAS member where entry is free for most travellers, Mauritania does not belong to that area: a visa is generally required, to be confirmed before departure with the Mauritanian consulate or diplomatie.gouv.fr, the conditions changing regularly by nationality.
Without a written agreement or complete documents, it is better to give up the crossing than to negotiate at the border post: this is precisely the kind of journey where a with-driver option from Saint-Louis saves a lot of complications, the driver knowing both crossings and their respective formalities.
Frequently asked questions
In most cases yes, as Mauritania is not an ECOWAS member. Check the exact conditions for your nationality with the Mauritanian consulate or diplomatie.gouv.fr before you leave.
Rosso suits you if you arrive from the east of the country and accept the wait for the ferry. Diama, via the Diawling park, offers a more direct and predictable crossing from Saint-Louis, at the price of a track that is sometimes tricky in the rainy season.
Only with the rental company's prior written agreement: leaving the country is excluded by default from most standard contracts. Ask the question before booking if your route includes this crossing.
No, the crossing is still made by ferry at Rosso in 2026, the bridge project still being under construction. Diama remains the only fixed crossing option on this axis.
- ▸Police and gendarmerie checkpoints: papers, behaviour, good practice
- ▸Tracks in Senegal: laterite, the rainy season, when a 4x4 is essential
- ▸Driving at night in Senegal: the real risks and precautions
- ▸Senegalese highway code: speed limits, priority, local specifics
- ▸Fuel in Senegal: prices, stations, jerrycan, range
- ▸Tolls in Senegal: Ila Touba motorway, Dakar-Diamniadio-AIBD, rates
In summary
Rosso or Diama, crossing the Mauritanian border is prepared with the same reflexes as crossing into the Gambia: complete documents, the rental company's written agreement if you are in a rental car, and a good time margin on the planned schedule.
Set off from Saint-Louis with an easy mind
A with-driver option takes care of the formalities and the choice of the right crossing into Mauritania.
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