While the size of your ship and the length of your cruise determine the variety and number of ports you visit, so will the type of itinerary. World cruises don't necessarily end at the point of departure, and segments are always one-way cruises that start at one point and end at another.

These are the most ambitious cruises that touch all continents and usually last over three months. Vying with one another to offer the most interesting itineraries to culturally enriching destinations, each cruise is unique, yet all offer a wide array of far-flung port calls. World cruises typically visit as many as 40 to 45 ports of call in 25 to 31 nations and touch from five to seven continents. Most world cruises begin in Florida, either in Miami or Fort Lauderdale, head to South America and turn west around Cape Horn and into the Pacific. They proceed on their westward voyages to a variety of Pacific islands, Australia and New Zealand, Far Eastern and Asian ports, and on to the Middle East and Mediterranean before arriving at their final ports, either London, New York, or South Florida. Exceptions are Crystal Cruises and Regent Seven Seas Cruises, which set off in an easterly direction after reaching South America to stop in South Africa and from there head to Asia before doubling back through the Mediterranean. UK-based cruise lines usually begin their world cruises in Southampton or Dover but sail west to encircle the globe.

Even a segment of a world cruise can be a fulfilling voyage for travelers with time (or money) constraints. World cruises are generally broken down into segments ranging from as few as 12 days to as many as 70 or more days. Two or more segments can be combined for an exotic slice of the world; for instance, a segment from Singapore to Dubai might be followed by a segment from Dubai to Alexandria, Egypt.