Relativistic quantum mechanics typically isn't covered during undergrad. Maybe touched on briefly.

Cambridge Physics Part II (third year of the Natural Sciences tripos) includes relativistic QM as a core 3rd year topic.

The Cambridge Physics course is fairly hard core of course, but I would expect such a course to be part of any serious Physics undergraduate degree in the UK.

I don't know what university you went to, but it definitely was on my course. Second or third year. The idea that you wouldn't cover relativistic QM in undergrad physics is pretty absurd, and probably indicative of how shallow American undergrad degrees are.

Defensive American undergraduate educated anecdote: my degree was in computer science and I studied this third year. Can't speak for anybody else.

Computational QM is a thing these days :)

Yep, didn't mean to suggest the course is irrelevant to computer scientists. I meant to imply that if they're teaching it to CS students third year, presumably physics students are learning it earlier and/or in more depth.

There are ~2,500 institutions in the U.S granting bachelors degrees, and you're happy to make sweeping generalizations about all of them.