Lambis truncata is the largest and heaviest of spider shells, up to 40 cm. Lambis truncata is similar to Lambis lambis but with a more squarish outline. The distribution of Lambis truncata includes the Indian Ocean off Aldabra, Chagos, Madagascar, Mauritius, Tanzania; the Bay of Bengal and in the Pacific Ocean along the Philippines.

2 subspecies, Lambis truncata truncata has a flat apex, while the apex of Lambis truncata sebae is more pointed.