When traveling from abroad you need a visa to enter Kenya. You can either get a visa on arrival at the airport, or before you travel. To minimise time spent queuing at the airport, it is advisable to get a visa before you travel. You can apply for single entry and transit visas on the evisas website. For other types of visa, apply at the nearest Kenyan High Commission or Embassy. For more information on different types of visas see the website of the Kenya High Commission.
Your passport should be valid for a minimum period of 6 months from the date of entry into Kenya. Make sure you have two blank pages in your passport on arrival.
Yellow fever vaccination is required for travellers arriving from countries with risk of yellow fever transmission. This requirement is being increasingly strictly enforced.