Ships in the Culture are intelligent individuals, often of very large size, controlled by one or more Minds. The ship is considered the Mind's body. Some ships (e.g., GSVs) are tens or even hundreds of kilometers in length and may have millions or even billions of residents who live on them full time, and together with Orbitals represent the main form of habitat for the Culture. Such large ships may temporarily contain smaller ships with their own populations, and/or manufacture such ships themselves.

In Use of Weapons, the protagonist Zakalwe is allowed to acclimatise himself to the Culture by wandering for days through the habitable levels of a ship (the GSV Size Isn't Everything described as over 80 kilometers long) eating and sleeping at the many locations which provide food and accommodation throughout the structure, and enjoying the various forms of contact possible with the friendly and accommodating inhabitants.