There are three race categories; The Full Marathon, Half Marathon and Children's Race. The races start at 7.00 am at the southern end of the conservancy. The course is set on dirt roads that take the runners on an undulating 13 mile course through the reserve, across Savannah plains, along river banks and through acacia woodland before finishing close to Lewa’s headquarters.

Half Marathon runners complete one loop of the course, Full Marathon runners, two. The route is watched over by a large and experienced team of armed rangers, with two helicopters and a spotter plane in the air throughout the race. Water stations and first aid points are situated every 2.5 km along the course. Medical support at the finish is provided by AMREF - the flying doctors, the Kenya Red Cross and local hospitals. On completion of the race each runner is presented with a medal and goody bag.

The impact of the event has been huge and the benefits are very tangible. Since its inception, the event has raised over $5million - last year's race alone raised $640,000. Tusk and Lewa have always shared a common goal to use wildlife conservation as a catalyst to alleviate poverty, reduce conflict, and improve education and livelihoods in rural areas rich in biodiversity. The Safaricom Marathon is unique and must not be viewed like the many City marathons held around the world.