Nairobi suffers from much of the crime that any major Western city does, and women should not be deterred from traveling to Kenya for fear of becoming a victim of these crimes. There may be some additional or specific advice to consider, but like any major city general common sense holds true in Kenya and throughout Africa. It should be kept in mind that while crime does occur at tourist sites in Nairobi, most of the crime is committed in the slums on the outskirts of Nairobi. This does not mean that you are immune or that general precautions taken in Western cities are all you need to keep safe in Africa.
In most African countries it is generally advised not to walk alone at night and to take a cab, even if you are only traveling a few blocks. During the day in Nairobi it is generally much safer, but you should still be sure to watch your belongings and not to wear or carry expensive jewelry or electronics. Carrying low sums of cash is advised as well. In terms of which taxi to chose taking with you the names and numbers of reliable taxis is suggested rather than hitching a ride with an unlicensed taxi. Two companies are Jatco, +254 (20) 4446096 or Kenatco +254 (20) 2225123. Both companies accept reservations on their websites. Taking matatus for transportation may seem fun, but these vehicles are generally unsafe and are driven by poor and unsafe drivers. There have been reports of these matatus being hijacked by thugs and passengers being robbed, although you are much more likely to be pick pocketed. It is best to avoid them altogether.
If you are renting a car you should take extra precautions, as car hijackings are common. Keeping your windows rolled up and your doors locked while driving, especially at red lights and stop signs, are essential. If you are the victim of a car hijacking attempting to escape or resisting the robbery is advised against and most tourists are able to escape unharmed if they hand over their cash and other valuables to the thieves. Car hijackings are frequent on the unfinished Nairobi ring road that leads from the airport to Ngong Road just outside Karen.
The largest crimes committed against tourist are pickpocketing and theft. Street muggings are very common and there are several ways you can reduce your exposure to them. Avoiding abandoned or desolate roads and alleys, and ignoring street children who may be trained in scamming western tourists. Also, you should not accept food or drinks from strangers as there have been instances where tourists were drugged and robbed.
There is more specific advice tailored to women, which you may find useful. Never admitting that you are traveling alone to strangers and even wearing a fake wedding ring to deter unwanted advances are two basic ones. Personally, I have never tried the wedding ring tactic and this may backfire and thieves could view this as a piece of jewelry to steal. Generally speaking, in Kenya women should not wear clothing that reveals their shoulders or their legs. Kenyan women do not generally wear shorts and tank tops and dressing more conservatively is a good decision. This is especially true outside of Nairobi.
All parks should be avoided at night and Uhuru Park should be avoided even during the day. Uhuru Park is a frequent location for political demonstrations and rallies and also is a gathering place for thugs. Other areas in Nairobi to avoid are staying in hotels beyond Tom Mboya Street and the area around Latema and River Roads, as this is a frequent area where petty theft occurs.
If you become ill or need medical attention, although Nairobi houses the most advanced medical facilities in East Africa, there are still many concerns. If you are seeking medical care, you should avoid Kenyatta National Hospital. Two other medical facilities to go to include: Nairobi Hospital (722160) off Argwings Khodek Road or Aga Khan Hospital (740000) open 24 hours and on third Parklands Avenue. Emergency services may be contacted at 999, although you should not rely on prompt arrival of these services. For non-emergency police business you may contact 240000. You may and should always try to contact the U.S. Embassy or Consulate for assistance on medical advice, if you lose your passport, or are a victim of crime. It is suggested that you should inform the Central Police Station on University Way, but with limited resources and rampant corruption, you should not expect the same care you would receive in a western country.
During my stay in Nairobi I stayed at the extremely safe Kivi Milimani Hotel, which is located 30 minutes from the airport and 2 kms from the city center. There are many other budget options you can find on hostelworld.com which typically include user comments and suggestions including ratings on safety and security.
Nairobi and Africa may have bad international reputations, but with a couple extra precautions you can try to avoid being the victim of crime. Most importantly, how you react to the crime dictates not only how your trip is, but also if you are able to get away unscathed. I am a single, young, Caucasian female that traveled to and around Nairobi myself without so much as the slightest problem, so it certainly is possible.