Naval forces in All Union’s Soviet Romanian War were bound to play a peripheral role. Romania had a small and weak navy, a relatively short coastline, and massive conventional amphibious landings were geographically dubious and militarily even more so. Constanta was overrun and surrendered almost immediately after the war began. Even Soviet historiography talks very little about what they and the Bulgarians did at sea, mostly just mentioning bombardment, surveillance, transport, and other routine supporting tasks. Most naval infantry units fought on land.

Yet it would be a mistake to assume that the navies did nothing or that there was no drama. Although overshadowed by the crossing of the Danube and the massive deep airborne operations, one of the largest postwar aerial/amphibious landings was conducted in Tulcea County.

• Units near Bolhrad would cross/lift/fly over or infiltrate via smaller boat.
• Heliborne units from the Black Sea would stage and make large landings in the depths. Black Sea Fleet aircraft and ships would naturally support them.
• The Tulcea operation was considered lower priority and was assigned fewer resources and, uncharacteristically, had its commanders given instructions to not try and force it if the initial advance stalled. (In contrast, the Danube Front units tasked with taking the Constana area were told to rightfully treat it as a high-priority one).

Notable events:

• September 8-9: Landings. Many inoperable Romanian ships destroyed in port.
• September 8: Romanian corvette M290 sunk by SS-N-14 missile. Romanian submarine SC-02 sunk.
• September 9: Sole successful Romanian air attack against Soviet Warships. Missile craft Kittivyek sunk by Romanian MiG-21s. Two other unsuccessful attacks. Five aircraft and four ASMs shot down.
• September 10: Gunboat PSKR-710 destroyed by mine. Four Romanian craft sunk. Romanian submarines Pastrav, SC-01 sunk.
• September 11: Final attempted Romanian air/missile attack on naval targets. Completely unsuccessful. Romanian submarine SC-05 sunk by Soviet submarine S-39 in the first post-WW2 mutually submerged sinking. Soviet landing ship SDK-303 sunk by mine.
• September 13: Tulcea operation completed with mutual link-up.
• September 14: Final surface engagements of the war, a duel between small boats in the north and Bulgarian ships sinking an attempt to flee southeast into the open ocean, presumably to Turkey.
• September 16: Final naval engagement. Romanian submarine Ton sunk.

The main takeaway was that ASW was successful (no Soviet ships lost, no disruption) but it was under ideal circumstances (being able to just smother a small area).