Crackle, Fandango at Home, and Tubi have great collections.
None of these websites offerjustaction films.
Many of my picks below also includedrama moviesand other genres.

Crackle
Don’t have to make a user account.
Support for subtitles and captions.
Movies are regularly rotated and removed from the list.

Can’t sort by popularity.
Crackle has a large assortment of dozens of action movies and TV shows.
Fandango at Home
Lots of high-quality movies.

Not everything you find is free to watch.
Ads are in every film.
Some movies on Fandango at Home are available only at a cost.

To verify you’re selecting only the movies with ads, look for titles that sayFree With Ads.
Tubi
Multiple video playback quality options.
“Only Free on Tubi” section has films you won’t find elsewhere.

Long list of action films.
Not available in Europe and some other countries.
Videos include lots of repetitive ads.

Can’t sort the movies.
TV shows are mixed into the same list.
Another source with hundreds of options is Tubi.

Amazon Prime Video
High-quality options.
Browse by action subgenres.
Can’t sort by popularity or recently added.

Must access to watch anything.
Find obscure older films and shows you won’t see elsewhere.
No page that shows just the action films.

Only around 100 movies marked as ‘action.’
Must have a YouTube account.
YouTube maintains a list of these films through the link below.

There’s a whole section just forAction & adventurefilms.
The Roku Channel
Great selection.
No user account required.
Films can’t be sorted by date or popularity.
Must scroll left to right to view the movies.
Movies and shows are mixed in together.
Although the Roku Channel looks like a Roku-only streaming service, it runs from a computer, too.
Pluto TV
On-screen guide automatically adjusts to your timezone.
Supports 4K streaming for some channels.
Has live and on-demand films.
Can’t filter the on-demand titles by popularity.
Pluto TV has an always-on, live TV channel showing action movies all day, every day.
Another way to find free movies here is throughtheir long list of on-demand movies.
Plex
Lots of extra movie information.
Easily locate other movies with the same actors.
Must access to see the full list of movies.
Plex has loads of movies in a handful of traditional genres, including action.
Filmzie
Great place for titles you’ve never heard of.
Add titles to a watchlist.
Can’t sort the list by popularity, rating, etc.
Doesn’t verify your age for NC-17 movies.
If you’re looking for hidden gems, Filmzie is the place for it.
Yidio
Collects links to movies hosted on other streaming sites.
Not all movies are free to watch.
Video playback quality is good but inconsistent.
Must watch the movies on other sites.
Yidio is a bit different than these other sites because its more like a search engine for movies.
It searchesothermovie streaming sites for movies and then provides links to watch them.