If I load a video from the internet, will I still be able to watch it if I no longer have internet access?

This is probably a stupid question, but I’m writing a report on this hearing for work, and I was hoping to watch the video on the train before work tomorrow morning. If I load the video up in the morning prior to leaving for work, will I be able to watch it on the train (where I have no wifi access)? Thanks for any help!