Citizens of all Western nations need a visa to enter. Holders of West African passports do not require a visa.
As of 2009, visas for Mauritania are no longer available at on arrival at land borders, so overland travellers have to arrange them in eg. Rabat. Single entry visa fee is 37 EUR, double entry is 52 EUR. Two passport-size photos are required, as well as a copy of the information pages of your passport. Visas are available on the next day for people of most nationalities. As of January 2012 this is true for Americans as well, although it is advisable to check that there have been no recent issues with long waits, so your travel plans are not interfered with.
For most people there are no vaccinations required in Mauritania. Only ones coming from yellow fever endemic zones are required to present a vaccination certificate.
By train
No trains run between Mauritania and its neighbors.
By Bus/Bush Taxi
From Morocco: Supratours runs a nightly bus to the border at Gargarate. It departs from the Dakhla waterfront at 23:59 and arrives at the frontier at 05:30 for 150 Dh. CTM the Moroccan national bus company is planning to run services from Dakhla to Nouakchott. Access is currently available by hitching with overlanders from Dakhla most can be picked up from Camping Moussafir just north of Dakhla or from the Mauritanian embassy in Rabat, or by paying for passage with Mauritanian traders. These can be found opposite the first police checkpoint north of Dakhla, the going rate is currently 250-380Dhs negotiable the ride should be started rather early and takes most of the day and border crossing is closed overnight. Cars with experienced drivers can be organized from Hotel Sahara the budget one. This costs around 250Dhs per person. Be careful to avoid a driver with an obvious facial pigmentation disorder. He has been known to behave aggressively towards passengers.
To Morocco: Cars with drivers can be arranged to cross the minefield from Mauritania to Western Sahara from Hotels in Nouadhibou.
From Senegal: Bush taxis can be taken from Dakar 6,000 CFA and St Louis 2,000 CFA amongst others to Rosso, where a ferry makes the trip across the Senegal river, and further bush taxis can be taken to Nouakchott about 2,000 UM. Be careful of bush taxis offering deals that seem too good to be true. They may be illegal taxis and could prove to be a dangerous means of transportation. There will most likely be a number of drivers waiting. Ask around and find out the going rate. Other crossing points from Senegal include the Diama dam just north of St Louis, public transport also operates on this route.
From Mali: Pickup trucks leave Kayes for Selibaby daily. It is also possible to enter at Nema, and across the southern border at several points.
By car
Mauritania has open road borders with Western Sahara, Mali and Senegal. These borders are open to crossing by private motor vehicle or bicycle.
The road from The Western Sahara/Morocco enters the country near Nouadhibou. The road is paved all the way to the Moroccan border post in Fort Guerguarat, where one has to traverse about 7 kilometers of twisting, stony, but straightforward pistes to reach the Mauritanian border, where the tarred road begins again. Although the driving is simple, care should be taken not to leave the well worn pistes between the two border posts, because the area is a mine field. This danger is still present once you reach the tar on the Mauritanian side, and the area is not considered mine-free until you pass the railway line.
The crossing formalities are straightforward. Transit visas - valid for 3 days - can no longer be bought at the border, although this may change again. There is a bureau de change at the border, and a vehicle insurance office and numerous hopeful guides for making the old desert crossing down to the capital.
There are numerous pistes running across the Mauritanian border from Mali. These used to be the de facto route between the two countries, however there now exists a new tar road connecting Nara in Mali to Ayoun al Atrous in Mauritania. The border formalities in Mali are completed at various buildings around Nara town local children will lead you to the police or customs for a small present. The Mauritanian formalities are conducted at a string of road-blocks along the border road.
An alternative land route which goes direct from Mauritania to Timbuktu, Mali is to travel the road Southeast from Néma, which is at the end of a good tarred road from Nouakchott. This dirt road continues to Bassekounou before crossing the border near Léré, Mali where it improves to a good dirt road to Niafunké and on to Timbuktu.