As with all of HBO’s shows, you won’t find The Leftovers on Netflix or Hulu anytime soon. There have been tensions in the past between Netflix and HBO in particular that make that reality very unlikely any time in the next decade or so.
You can, however expect to see The Leftovers on Amazon Prime but not for about three years. Amazon recently signed a major deal with HBO allowing them to stream all of their older episodes to Amazon Prime members so be sure to check that out. HBO series, in the USA at least, are not typically available on any other streaming platform either.
Get more info on how to watch The Leftovers online or streaming for free at HBOWatch.com.
For a list of all the online movies and TV shows that are currently streaming on Netflix, go to www.justwatch.com and www.whats-on-netflix.com.