Yes, it's is a submersible, but it is also a drone.
reply> Which is notably not going to be launching a drone the size of a even a Shahed, nor anything close to the same range.
It doesn't need to. It is its own munition with a anywhere from 500 to a couple of tons of explosives on board. And a very impressive range.
Why might the US be using air power to strike targets which are inland in Iran?
replyWhat characteristics of a submarine might be considerably problematic to doing that?
Would these problems perhaps also effect a defensive mission to prevent air strikes on ships in the Strait of Hormuz?