There is no road to Bilma in any conventional sense. The 600 km from Agadez crosses the worst of the Tenere — soft sand, no fixed track for long stretches, no water and no settlements between the two. Expect three to four days each way in a 4WD convoy. Guides, two vehicles minimum, satellite phone, fuel and water for double the planned distance are the standard precautions.
The handful of organised desert tours that still operate out of Agadez make the trip seasonally, usually as part of a longer loop that takes in the Air mountains as well. Independent travel is not advised: there are landmines along the Libyan border to the north, banditry along the route, and a permanent risk of vehicles breaking down in places where nobody else will pass for days.
Light aircraft occasionally fly into Bilma's airstrip for special charters; there is no scheduled service.