This article asks various Navy men their thoughts. This one by Lieutenant Commander Jeff Vandenengel stuck out.

- Office Space is the best submarine movie. TPS reports, multiple bosses, a defective printer, coming in on Saturday, the oversight team of “the Bobs” that are “there to help,” and the engineers are not allowed to talk to normal people. Incredibly accurate!

It looks like senior officers are a bit over-represented in this survey, not surprising since it came from the US Naval Institute. Senior Partridge seems to be the only one willing to admit that Down Periscope does a surprisingly good job of capturing the inanity and absurdity of submarining. I’d argue Office Space, mentioned in a sibling comment, underrepresents the suck for the Wardroom, Nukes, and possibly MTs.

Before reading TFA I was going to post:

https://en.wikipedia.org/wiki/Das_Boot

And after reading TFA I can see it's the most voted one. I don't know if it's the most realistic one but, sheesh, does it feel claustrophobic and stressful!

It's a brave man indeed who volunteers after watching Das Boot (2nd from the end in the article).

Why not ask the actual crew?

Just watched this last week about the USS Oregon, and the crew were asked their favourite sub movies...

https://youtu.be/YeVsxF-MVQE?t=394

Sounds like the German film Das Boot is a winner (the German version of All Quiet on the Western Front is also amazing. Looks like the German film industry is doing well).

My fave was the burb by Lieutenant Commander Jeff Vandenengel (U.S. Navy).

It was an absolute given that Das Boot would by far be the first movie mentioned by so many of them in this post. It was the instant first movie that came to my mind and nothing comes quite close, even today, decades later. An absolute masterpiece of serious film making.

Fun facts now: the cast of Das Boot was obliged to constantly stay indoors during the entire length of filming, forcefully as part of an effort to both give them a grossly pallid, sickly complexion like you'd expect from a WWII era submariner at sea for months, and to create a sense of claustrophobia that would percolate into more realistic acting.

Also, the mockup of the submarine's interior was built for maximum realism in its size and all usable physical details, with the actors rigorously trained to move through this space as naturally as possible (as a real German U-boat crew would)

The effort, along with the great script, fantastic cast and of course, memorable music, shows in pretty much everything, right down to the disgusting details of how they look and act after weeks at sea. One hell of a movie, and while my personal experience with submarines is zero, this is the one that feels like it should be absolute most realistic depiction of crewing a sub from that era. It fully deserves its rank as one of the most highly rated films of any kind on most movie ranking websites, like IMDB and etc.

I can also see why it's the most highly voted film among submariners. Even if modern nuclear subs are at a whole other level of comfort compared to anything from 85 years ago, certain basics stay the same: It's a claustrophobic, fully enclosed space with nothing but artificial lighting, observation almost entirely through instruments, and crushing, nearly inescapable, horrible death just a few inches of hull and a couple sudden mistakes away.

All this is the case in a way that just doesn't apply to the same degree with any surface vessel, where you can still somehow feel directly connected to and within reach of the wider, comforting world.

It probably has more in common with space travel than being out at sea in these characteristics.

A little OT, but the funniest sub movie has got to be "Operation Petticoat", with Cary Grant and Tony Curtis at their best. And it does have a real (though pink) WW2 sub in it.

Das Boot is probably the most realistic. For more drama, Crimson Tide is a good watch. The Hunt For Red October is more of a fantasy, but also good drama.

Very amused that someone picked Down Periscope, which for some reason is where my mind immediately went.

Das Boot's soundtrack also takes the cake for me. Just compare the main title themes for Das Boot and Red October; both are good, but Das Boot's make you feel like you are in a submarine. The combination of synths, mechanical sounds, and even the sonar ping sound really adds to the artificality and claustrophobia.

I guess it's good to validate the answer, but I would have guessed Das Boot going in, and the answers merely confirm that I already knew the answer. The couple of exceptions are interesting though.

Yellow Submarine, clearly.