Cruise ships are large passenger ships used mainly for vacationing and travelling purpose. Unlike ocean liners, which are used for transport, they typically embark on round-trip voyages to various ports-of-call, where passengers may go on tours known as "shore excursions." On "cruises to nowhere" or "nowhere voyages", cruise ships make two- to three-night round trips without visiting any ports of call.

Sometimes the most remote and amazing places can only be reached by the oceans only, and the best way to get there is on an adventure cruise. Much smaller than normal cruise ships they can access more unusual ports and natural areas that the larger cruise ships cannot. These smaller ships can get you very close to massive icebergs and giant whales in Antarctica or wind their way through the smallest tributaries of the river Amazon.

As of December 2018, there are 314 cruise ships operating worldwide, with a combined capacity of 537K passengers. Cruising has become a major part of the tourism industry.