Is it legal to use a VPN to watch foreign movies online?

Yes, you can definitely use VPNs to watch movies that aren't featured in your current country of residence. Due to geo-blocking, some movie and TV series providers (like Netflix or Hulu) might hide certain TV shows or movies in specific countries. Usually, this is because of legal reasons, yet the movie-fanatics are the ones that get the worst end of the bargain. However, you can use a VPN to temporarily "relocate" in another country where your favourite TV shows & movies are featured, and you can enjoy watching them even if you're in located in a place where the content is geo-restricted.