The queen conch is herbivorous and lives in seagrass beds, although its exact habitat varies during the different stages of its development. The adult animal has a very large, solid and heavy shell, with knob-like spines on the shoulder, a flared thick outer lip and a characteristic pink-coloured aperture (opening). The flared lip is completely absent in younger specimens. The external anatomy of the soft parts of L. gigas is similar to that of other snails in the same family; it has a long snout, two eyestalks with well-developed eyes and additional sensory tentacles, a strong foot, and a corneous, sickle-shaped operculum.
The shell and soft parts of living L. gigas serve as a home to several different kinds of commensal animals, including slipper snails, porcelain crabs and cardinal fish. Its parasites include coccidians. The queen conch is hunted and eaten by several species of large predatory sea snails, and also by starfish, crustaceans and vertebrates (fish, sea turtles and humans). The meat of this sea snail is consumed by humans in a wide variety of dishes. The shell is sold as a souvenir and used as a decorative object. Historically, Native Americans and indigenous Caribbean peoples used parts of the shell to create various tools.
International trade in queen conch is regulated under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) agreement, in which it is listed as Strombus gigas. This species is not yet truly endangered in the Caribbean as a whole, but it is commercially threatened in numerous areas, largely due to extreme overfishing; the meat is an important food source for humans. The CITES regulations are designed to monitor and control the commercial export of the meat of this species, as well as the shells (often sold to be used as decorative objects). Both of these trades were previously so prevalent, they represented serious threats to the survival of the species. However, the CITES Convention does not monitor or regulate any domestic use.