First act (3 episodes) came out on Netflix today. 2nd act in a week, and last act a week after that
Alternate sources: Go to Yandex (dot) com and search "Arcane Season 2 stream online free". Yandex is a great resource in general for any free streaming, the first link always works perfect
First season is really, really good imo. Complex characters and emotional plots. Art might take a second to get used to, but once they started getting a experimental with it, I found myself liking it more rather than less (like with the Spiderverse movies). I like that it has materialist explanations even for the villains.
I need to watch the second, haven't started it yet.