'M.43' was an Italian troop and supply convoy operation from southern Italian ports to Tripoli on the north coast of Africa (3/6 January 1942).

On 3 January the Italians despatched three small convoys in the hope that that this widespread deployment would overextend any British attempt to intercept and thereby make it possible for some, at least, of the ships to reach their destination. Three freighters (7,137-ton Nino Bixio, 5,324-ton Monginevro and 6,070-ton Lerici) departed Messina under escort of the destroyers Ugolino Vivaldi, Nicoloso da Recco, Antoniotto Usodimare, Bersagliere and Fuciliere; the 5,322-ton freighter Monviso and 7,000-ton tanker Giulio Giordani sailed from Taranto under escort of the torpedo boats Orsa, Aretusa, Castore and Antares; and the 6,836-ton transport Gino Allegri left Messina under escort of the destroyer Freccia and torpedo boat Procione.

The convoys combined on the following day, and proceeded to the south with close support provided by Ammiraglio di Squadra Carlo Bergamini’s force comprising the battleship Caio Duilio, light cruisers Giuseppe Garibaldi, Raimondo Montecuccoli, Emanuele Filiberto Duca d’Aosta and Muzio Attendolo, and destroyers Maestrale, Vincenzo Gioberti, Alfredo Oriani, Lanzerotto Malocello and Scirocco, and distant cover by Ammiraglio di Armata Angelo Iachino’s force comprising the battleships Littorio, Andrea Doria and Giulio Cesare, heavy cruisers Gorizia and Trento, and destroyers Carabiniere, Alpino, Antonio Pigafetta, Antonio da Noli, Ascari, Aviere, Geniere and Camicia Nera. To the east of Malta, the operation’s western flank was shielded by the submarines Pisani, Onice, Dandolo, Alagi, Aradam, Tricheco and Axum, and in the area between Crete and Cyrenaica its eastern flank was protected by the submarines Beilul, Zaffiro, Dessiè and Galatea.

British sightings of the 'M.43' convoy by aircraft and the submarines Ultimatum and Unique did not pave the way to successful attacks, and on 5 January the convoy arrived safely in Tripoli. The Littorio force turned back toward Italy on the same day, and that of Caio Duilio on the following day. Unique made an unsuccessful attack on Littorio during her passage back to Italy.