Battle of Cape Matapan 150 miles West of Crete. At 6.35 AM, Italian Ro43 seaplane spots Allied cruisers HMS Ajax, Gloucester, Orion & HMAS Perth. Italian cruisers Trieste, Trento & Bolzano close in and open fire at 8.12 AM from 22km without success, then battleship Veneto joins in at 10.55 from 23km (shell splinters cause slight damage to all 4 Allied cruisers). Torpedo bombers from HMS Formidable attack Veneto at noon and again at 3.09 PM, hitting a propeller & causing flooding which stops her for 90 minutes (1 Albacore is shot down, all 3 crew killed). Admiral Cunningham immediately orders Mediterranean fleet to close on the damaged Italian battleship. Torpedo bombers from HMS Formidable and from Crete (815 Squadron) attack at 7.36 PM, crippling Italian cruiser Pola. Cruisers Zara and Fiume remain to help Pola while Vittorio Veneto and the other ships run for cover at Taranto. After dark, battleships HMS Barham, Valiant & Warspite close to 3.5km unnoticed by the Italian ships (which have no radar). They open fire at 11.30 PM, sinking 2 Italian cruisers Fiume & Zara and 2 destroyers Alfieri & Carducci while destroyer Oriani escapes with heavy damage (2,303 Italian sailors killed).
Eritrea, East Africa. Indian Pattern Carriers and armoured cars of Indian 4th & 5th Divisions pursue Italians East from Keren (2000 Italian stragglers taken prisoner). Italians mount a fighting retreat where the road towards the capital Asmara twists for several miles along the side of a valley, sloping steeply away into a gorge. They will hold the British and Indian advance with rocks blasted from the hillsides and hidden artillery, using guns withdrawn from Keren.
Italian torpedo boat Chinotto sinks in minefield off Palermo, Sicily, laid by British submarine HMS Rorqual on March 25. British submarine HMS Utmost torpedoes German steamers Heraklea (sinks) and Ruhr (damaged) off the coast of Tunisia.