Piaggio designed the P.23M specifically for flights across the North Atlantic Ocean, intending it to have potential for development as a commercial transport.

[1] It was a four-engine shoulder-wing monoplane with inverted gull wings and twin tail fins and rudders.

[1] To allow an easier landing if the aircraft had to ditch at sea, its fuselage was designed like a boat hull, which Piaggio termed an avion marin ("marine aviation") design, although the aircraft was not a flying boat.

The P.23M's four 671 kW (900 hp) Isotta-Fraschini Asso XI R. V-12 engines were mounted on the wings in two tandem pairs, each engine driving a two-bladed propeller; two of the propellers were mounted as pushers and the other two in a tractor configuration.

No attempt to fly the Atlantic Ocean ever took place, and its predicted maximum range capabilities never were tested.