The largest naval action fought by the Romanian Navy was the 26 June 1941 Raid on Constanța, and its most extensive operation was the 1944 evacuation of the Crimea.

The naval war in the Black Sea commenced with the Raid on Constanța on 26 June 1941, the only encounter between major warships during the entire campaign.

In the ensuing battle, the Soviet Shchuka-class submarine Shch-206 was attacked by Năluca, at first with 20 mm rounds and then with depth charges, eventually being sunk with all hands.

After attacking, the submarine was located by a German BV 138C flying boat, and the Romanian gunboats Sublocotenent Ghiculescu and Stihi Eugen were sent to the scene.

[16][17][18] Recent surveys in the area failed to find the wreck in the alleged sinking location and it has been raised the alternative version that M-118 was lost due German seaplane attack [19] or a Romanian field from barrage "S-30".

The last phase of the evacuation (10-14 May) saw the fiercest combat, as Axis ships transported, under constant attacks from Soviet aircraft and shore artillery, over 30,000 troops.

During the night of 27 April, a convoy escorted by the Romanian gunboat Ghiculescu, the German submarine hunter UJ-115, one R-boat, two KFK naval trawlers and 19 MFPs (including the Romanian PTA-404 and PTA-406) engaged the Soviet G-5-class motor torpedo boats TKA-332, TKA-343 and TKA-344, after the three attacked and damaged the German submarine hunter UJ-104 (never recovered).

[25] Between 7 and 16 October 1941, Amiral Murgescu along with two auxiliary minelayers, all three escorted by the Romanian 250t-class torpedo boats Năluca, Sborul and Smeul, the Romanian gunboats Sublocotenent Ghiculescu and Căpitan Dumitrescu and the Bulgarian torpedo boats Drazki, Smeli and Hrabri, laid four full minefields and one partial minefield along the Bulgarian coast.

[37][38] Submarine Campaign Romanian warships and marines in the Danube Delta supported the Romanian-German ground forces during their offensive into Bessarabia, at the start of July 1941.

Thus, the artillery of the Romanian 17th Marine Infantry Battalion, operating in the Periprava sector, shelled and sank six Soviet armored motor gunboats.

[43] The submarine was subsequently attacked by Soviet forces but she followed a route along the Turkish coast and managed to evade up to 80 depth charges, before safely arriving in the port of Constanța on 7 November.

[51] In addition, five Italian-built CB-class midget submarines were temporarily acquired in the autumn of 1943, however only two could be made serviceable before being returned to the Italian R.S.I.

[54] These supplemented the existing squadron of seven motor torpedo boats, consisting of the British-built Viscolul and the six Romanian-built Vedenia-class vessels.

The following major seaports were protected by Romanian mine barrages by the end of 1943: Romania capitulated on 23 August 1944, in the aftermath of a successful Soviet land offensive.

The older vessels were received in September 1945, while the more modern ones (such as the Regele Ferdinand-class) were kept by the Soviet Black Sea Fleet until the early 1950s.