Tourism is a major foreign exchange earner in Kenya contributing to 10% of the gross domestic product (GDP). Whereas Kenyan government strives to boost its GDP through improved arrivals, lack of effective tourism marketing strategies hinders growth in tourist arrivals in Kenya. To advertise and market the untold wealth of tourist destinations, the government utilizes campaigns through print and electronic media, which are expensive and limited in updating. This study addresses the gap by designing a web Geographic Information System (GIS) portal for marketing and promotion of tourism. To realize this a multimedia GIS database was created using PostgreSQL/PostGIS software to store spatial and multimedia tourism data, while itinerary planning tools were designed using Dijkstra algorithm and Travelling Salesman Problem (TSP) approach. The result was a web GIS portal interface containing tourist information enhanced with text and/or video/audio descriptions. Facebook advertisement was used to popularize the tourism products available in Kenya through visitor engagements as well as directing traffic to the portal fast and inexpensively.