For U.S. travelers heading to Africa, you need a passport that's valid for six months after your flight back to the States, though some tour companies recommend having your passport valid for nine months after, just to be safe [source: Eyes on Africa]. Most countries also want you to have two blank pages for their departure and entry stamps, so make sure your passport has two pages for each country you'll be leaving and entering.
Heading to Botswana, Malawi, Mauritius, Namibia, Rwanda, Seychelles, or South Africa? You don't need a travel visa to enter these countries if you're a U.S. citizen – just a passport will do the trick. For countries that do require a travel visa, some allow you to purchase one when you arrive and others want you to have it in advance. Kenya, Mozambique, Tanzania, Uganda, Zambia and Zimbabwe let you buy when you get there, and you should bring U.S. dollars in cash to pay for it. If you're headed to Egypt or Madagascar, make sure you get that visa sorted out before your trip [source: African Portfolio]!
Passport and visa requirements vary by country and can change without notice, so when you're planning your trip make sure you check with your travel agent or the embassy of the country you're planning to visit. Most countries have a Web site advising visitors of the visa and passport requirements – and they vary depending on your nationality. If you're a U.S. citizen, you can also use the U.S. Department of State's Web site which lists visa requirements for various countries. Some countries also require visitors to pay a departure tax.