Crunchyroll holds the largest legal library of Detective Conan episodes. However, note that they use the Case Closed title for earlier seasons.
: The primary legal streamer for the series. You may need to browse to the specific season (often categorized under "Season 1" or specific year-blocks) to find it. detective conan episode 626 link
Many fans cry "dead link" because they are looking at the wrong numbering system. Crunchyroll holds the largest legal library of Detective