As we saw in the case of the “dead” Russian admiral who then turned out to be alive, Ukrainian reports of successes against can sometimes turn out to be a tad optimistic. Still, the Russian Black Sea Fleet has suffered significant losses since the invasion of Ukraine and it seems that these likely now include the Kilo Class submarine Rostov-na-Danu (Rostov on Don).
A russian submarine went to the bottom of the Black Sea.
Ukrainian defense forces successfully attacked the B-237...
https://www.marinelog.com/news/ukraine-reports-that-it-sank-russian-kilo-class-submarine/