[4] They carried enough fuel oil to give them a range of 3,200 nautical miles (5,900 km; 3,700 mi) at a speed of 14 knots (26 km/h; 16 mph).

[1] Upon her completion Zeffiro, together with Espero, Ostro and Borea, was assigned to the 1st Squadron of the I Destroyer Flotilla based at La Spezia.

[7] In 1934 after another reorganization Zeffiro as well as Espero, Ostro and Borea were again reunited, now forming the 4th Destroyer Squadron, part of II Naval Division.

On 3 August 1937 Franco made an urgent plea with Mussolini to use the Italian fleet to prevent the passage of a large Soviet transport convoy, which just departed from Odessa.

[9] In September 1937 the Nyon Conference was called by France and Great Britain to address the "underwater piracy" conducted against merchant traffic in the Mediterranean.

On 14 September an agreement was signed establishing British and French patrol zones around Spain (with a total of 60 destroyers and airforce employed) to counteract aggressive behavior by submarines.

At the time of the Italian entrance into World War II on 10 June 1940, Zeffiro together with sister ships Espero, Ostro and Borea formed 2nd Destroyer Squadron based at Taranto.

On 27 June 1940 Zeffiro sailed from Taranto at 22:45 for the first war mission, along with Ostro and the squadron leader Espero (commanded by captain Enrico Baroni).

The three vessels were to transport to Tobruk two anti-aircraft batteries (10 Breda Model 35 cannons in all), 120 short tons (110 t) of ammunition (450,000 rounds) and 162 members of the Voluntary Militia for Territorial Security.

[10] On 28 June 1940 at 12:10, about 50 mi (43 nmi; 80 km) west of Zakynthos, the convoy was sighted by a British reconnaissance Short Sunderland plane.

The Italian destroyers were theoretically faster than the British cruisers, but due to their age and heavy cargo on board their speed advantage was nullified.

Espero laid smokescreens and conducted evasive maneuvers, engaging Liverpool's division with guns, and simultaneously firing three torpedoes at Orion.

In the late afternoon a group of nine Fairey Swordfish torpedo bombers of 813 Naval Air Squadron took off from the airfield in Sidi Barrani and headed towards Tobruk.