During its deployment to Ukraine, the unit has suffered heavy losses, with the Institute for the Study of War reporting that the brigade had been destroyed and reconstituted eight times by March 2023.

[11] On March 13, in a written post on Facebook, Ukrainian journalist Roman Tsymbalyuk reported that units of the 155th Separate Marine Brigade had suffered losses consisting of "about 600 servicemen killed and as many wounded" in the Chernihiv region.

[14] In early November 2022, there were reports of heavy losses in the brigade in battles in the Pavlivka area near Vuhledar in the Donetsk region.

[21][22] According to the Institute for the Study of War, the footage shows Russian forces engaging in "highly dysfunctional" combat tactics, which is likely an indication that the 155th brigade is made up of poorly trained, freshly mobilized soldiers.

[24][3][4][5] On February 27, 2024, a HIMARS strike killed 19 Russian soldiers from the 155th Naval Infantry Brigade including a colonel and 2 other ranking officers.

[29][30][31] In March 2023, Reporters Without Borders identified the 155th brigade as one of the Russian units present in the area at the time of the murder of Ukrainian photo-journalist Maks Levin and his friend in a forest north of Kyiv on April 1, 2022.

[32] In August 2024, members from the brigade allegedly beheaded four Ukrainians and displayed their severed heads on poles, behaviour usually associated with Islamic terror groups.