Since you’re looking to watch in English Dub, the best legal way to do it for free is through Crunchyroll . Where to Watch for Free (Legally)
: You can watch most seasons of SAO, including the original English Dub, for free with ads . Note that while the website is free, you may need a Premium account for certain high-definition features or to watch without commercial interruptions. Which Episode 10 Watch Sword Art Online (Dub) Episode 10 for fre...
Because the series is split into multiple seasons and arcs, "Episode 10" can refer to a few different major plot points: Sword Art Online Episode 10 Since you’re looking to watch in English Dub,