10 Jun, 1942
Vasilissa Olga picks up 58 men from the British tanker RFA Brambleleaf that was torpedoed and damaged by the German submarine U-81 off Ras Alem, Egypt in position 31º12'N, 28º10'E.

15 Dec, 1942
The Italian submarine Uarsciek (620 tons) was sunk south off Malta by the British destroyer HMS Petard and the Greek destroyer Vasilissa Olga.

19 Jan, 1943
The British destroyers HMS Pakenham, HMS Nubian and the Greek destroyer Vasilissa Olga intercept and sink the German transport ship Stromboli (475 tons) off the Libyan coast.

2 Jun, 1943
The Italian torpedo boat Castore (652 tons) left Taranto at 2000hours on 31 May 1943 as escort of the Italian merchants Postumia (595 GRT) and Vragnizza (1592 GRT) heading for Messina. Around 0140 hours on 2 June 1943 while off Cape Spartivento this convoy was attacked with gunfire by the British destroyer HMS Jervis (Capt. J.S. Crawford, DSO, RN) and the Greek destroyer Vasilissa Olga (Lt.Cdr. G. Blessas, DSO, RHN). The two Allied destroyers opened fire at 2000 yds and in the resulting action the Castore was sunk (around 0315 hours) and the two merchants were damaged. According to the war diaries of the Seekriegsleitung both merchant vessels are reported to have arrived in Messina at 1630 hours on 3 June. Other sources give that Postumia went ashore and was later raised and repaired. During the engagement Jervis and Vasilissa Olga were assisted by allied aircraft that illuminated the targets by firing flares.