Yes you require a valid passport and visa to enter Kenya, Uganda and Tanzania and Rwanda.
Please make sure that your passport is valid for six months from the date of your safari and that it has a sufficient number of unused pages for endorsements. We suggest that you take two photocopies of the information page of your passport and keep one in a separate part of your luggage and give the other to our East African partners during your orientation meeting upon arrival in East Africa. We also recommend leaving a copy with your contact person at home. If you lose your passport, this will make it easier to replace.
Please do not leave your passport or any other valuables in hotel rooms or unsupervised vehicles, planes, etc., while you are on safari.
Visas are available in your respective countries from the Uganda embassy/high commission or, since many people prefer not to mail their passports to Embassy, Consulate or tourism offices, you can apply for your visa online for Uganda, Rwanda and Kenya and pay for it upon arrival at the airport.
The East African Visa costs US$100 and enables entry to three East African countries; Uganda, Kenya and Tanzania
Embassy Websites:
Kenya http://www.kenyaembassy.com/ US$ 50.00 per person
Uganda http://www.ugandaembassy.com/ US$ 50.00 per person
Tanzania http://www.tanzaniaembassy-us.org/ US$ 100.00 per person