The Latécoère 380 was a largely conventional flying boat design, being a parasol-wing monoplane equipped with sponsons set either side of the hull.

[1] The aircraft features an all-metal wing structure that consisted of two box spars set 2.2 m apart, tubular lattice ribs, and compression members that were braced by steel wires.

The hull's structure consisted of numerous frames that were joined by the keel, along with various keelsons and stringers to which the light metal exterior was riveted to.

[2] The aircraft's exterior was protected against the corrosive sea water via multiple measures, such as an oxidizing bath, a coat of white lead, and all fittings and joints being designed to be water-tight.

[4] The forward most compartment functioned as the manoeuvring port while on the water, having been furnished with mooring ropes, a grapnel, floating anchor, and a trap door.

To the aft of this was the primary baggage hold, followed by the pilot's room; this space featured sliding side and overhead windows, and could be equipped with dual flying controls.

[5] Cooling was achieved via radiators fitted to the lower side of the wing; these were sized as to be sufficient to effectively function even under the tropical conditions.