Man, 'JoJo's Bizarre Adventure' is one of those shows that just hooks you with its over-the-top style and wild storytelling. If you're looking to watch it online, I've got some solid options for you. Crunchyroll is my go-to—it's got all the parts, subbed and dubbed, with a premium subscription for ad-free binge-watching. Netflix also carries some of the later parts, like 'Golden Wind,' but their selection varies by region. Hulu’s another contender, especially if you’re in the U.S. They’ve got a decent chunk of the series, though it’s not as complete as Crunchyroll.
For free (but legal) options, Tubi and Pluto TV sometimes rotate episodes in their anime sections, though you’ll have to deal with ads. And if you’re into physical media, Blu-ray collections are out there, but they can be pricey. Honestly, Crunchyroll feels like the most reliable spot—it’s where I rewatched 'Stardust Crusaders' last summer, and the quality was top-notch. The community there’s pretty active too, so you can geek out in the comments while you watch.