
Shared Taxi
The taxis are white in color. They are almost always shared (4 passengers) unless you ask specifically to pay more to make it private. Negotiate the price before getting into one.
Minibuses
There are minibuses available for transport within the city.
Bus
There are four bus main companies in the city depend on your destination: Rimbo, Air, Maissage and SNTV (Sociéte Nigerienne de Transports de Voyageurs). The buses go as far asAgadez, Ouagadougou, Algeria and Chad. Buses within Niamey operate on a few routes.
Water transport
The Niger River runs through the city. However there is no regular boat service. There are small boats that will gladly take you along the river. They are much slower and more comfortable than buses.
References
http://www.lonelyplanet.com/niger/niamey/transport/getting-around#ixzz2whOQo6mb