Shell of moderate size, maximum height 53.7 mm (USNM 414911, Cabanas Harbor, Cuba), moderately inflated (diameter / shell height, mean 0.625 ± 0.028, n = 19, range 0.57-0.67), low-spired (aperture height / total shell height, mean 0.675 ± 0.028, range 0.63-0.72), and thick; The protoconch consists of two whorls, the first minute, the second inflated. There is no terminal protoconch varix, but instead a smooth transition from the protoconch to the axially ribbed first teleoconch whorl. Spiral sculpture of last whorl weak, consisting of extremely fine obsolete threads; upper and lower angulations often absent, but labral tooth always present even when central cord not well expressed; axial sculpture weak or absent on last whorl, often present as low ribs on early teleoconch whorls but never forming tubercles or nodes; when present on last whorl, axial ribs are nine to 11 in number, confined to upper part of whorl only; subsutural ramp usually absent; outer Hp medially convex, adapical sinus obsolete or absent; adaxial side of outer lip with up to 22 weak, beaded lirae; aperture relatively narrow, its height: breadth ratio usually 2.8—2.9; siphonal canal usually short (canal height / apertural height, mean 0.32 ± 0.04, range 0.22—0.39); siphonal fasciole distinct; umbilical slit absent; external color brown to almost black, sometimes with white striae, sometimes light; aperture white to peach-colored. The 68.0 mm specimen reported by Hutsell et al. (2001:53) from the Netherlands Antilles is probably L. nassa.

In the western Caribbean region, several populations of Leucozonia are characterized by relatively inflated, low-spired shells with strongly reduced spiral and axial sculpture and a variably expressed, but always present, labral tooth. Most shells have a white aperture, but in some populations (e.g., from West Caicos) it is peach-colored. Populations differ in the expression of ornament. No axial ribs are evident on the spire whorls in many populations.

For the most part, L. leucozonalis and L. nassa occupy different geographic regions within the western Atlantic. L. leucozonalis occurs on the south, east, and northwest coasts of Cuba, the north coasts of Jamaica and Hispaniola, in the southern Bahamas and Turks and Caicos Islands, in the Cayman Islands, and on the mainland coast from eastern Quintana Roo (Mexico) to Honduras. It also occurs at Isla Providencia, an island belonging to Colombia but situated in the western Caribbean off Costa Rica. L. nassa, by contrast, occurs in the Bahamas, northeast Cuba, the south coasts of Jamaica and Hispaniola, in Mexico from Vera Cruz to western Quintana Roo and Campeche, and on the mainland coast of Central America south of Honduras. It also occurs throughout the rest of the Caribbean and Florida, and on the mainland coast of South America to southern Brazil. The two species co-occur at a few localities, including Little Guana Cay, Abaco, Bahamas (ANSP 298418), and Bull Bay, St. Andrew's, Jamaica (ANSP 343283). Given this overlap in range, we tentatively regard L. leucozonalis and L. nassa as separate species. Tryon (1881) and Abbott (1958), by contrast, considered L. leucozonalis as a geographic subspecies of L. nassa.

Turks and Caicos Islands, northwest and south coasts of Cuba, north coasts of Jamaica and Hispaniola, Grand Cayman, east coast of Quintana Roo (Mexico) to Belize and Honduras and Isla Providencia (Columbia).