This site allows you to watch Castle episodes online. Yes, we allow you to watch castle absolutely free. We do this because we are also a huge fan of castle episodes. Every episode from the first season to the newest aired episode can be watched on this website. To watch an episode online, just click on the season and episode link to the left or simply press the post link right on the home page. If you enjoy watching Castle online, then we hope you spread the word so others can watch castle as well.