Soviet submarine ShCh210 goes missing off Cape Shabla, Bulgaria, presumably lost to a Romanian minefield.
In the North Sea, 20 miles off the English coast, German motor torpedo boats attack British coastal convoy FS749. Torpedo boat S-104 sinks British destroyer HMS Vortigern (110 killed, 14 survivors rescued by British patrol sloop HMS Guillemot).
245 miles Southeast of St. John’s, Newfoundland, a PBO-1 Hudson covering convoy ON-72 (Naval Squadron VP-82, from Argentia, Newfoundland) sinks U-503 with depth charges (all 51 hands lost). 15 miles off Cape Fear, North Carolina, U-158 damages US tanker SS Olean at 06.04 AM (6 killed, 36 survivors) and sinks US tanker SS Ario at 07.22 AM (8 dead, 26 survivors picked up by US destroyer USS Du Pont). 270 miles East of Palm Beach, Florida, Italian submarine Tazzoli sinks British SS Athelqueen (3 killed, 46 survivors). Tazzoli collides with SS Athelqueen, damaging the forward torpedo tubes, and is forced to abort the mission and arrives back at base in Bordeaux, France on March 31. At midday South of Haiti, U-161 sinks US Coast Guard lighthouse tender USCGC Acacia with 68 shells from the deck gun and 162 rounds from the 37mm & 20mm anti-aircraft guns (all 36 hands rescued by US destroyer USS Overton and taken to San Juan, Puerto Rico).
US Air Force 51st 67th Pursuit Squadron arrives by sea on the Free French island of New Caledonia, 950 miles East of Australia, to reinforce the Allied base with 45 P-40 fighters.
General MacArthur, his family and staff are evacuated from Mindanao Island, Philippines, to Australia on US B-17 bombers.