Why you should book through a cruise travel agentYou should consider booking a cruise through a travel agent because a knowledgeable agent can help you understand the nuances of a cruise purchase and help you make the best decisions for your vacation preferences. Cruise travel agents receive the bulk of their income via commission from the cruise lines. Companies such as Royal Caribbean and Carnival Cruise Line provide online directories to help you find an experienced cruise travel agent near you. LORRAINE BOOGICH/GETTY IMAGESYou can also find experienced and certified cruise travel agents through the Cruise Lines International Association, the industry's main marketing group. Questions to ask a cruise travel agentIn choosing a cruise travel agent, you will want to tap into the person's specific expertise about the cruise line and ship you are considering.