Tubi
Tubi is a US streaming service based in San Francisco, launched in 2014. It is available in the United States and Canada only.
The video-on-demand platform is free to use, but is ad-supported.
Over 600 episodes of classic Doctor Who (1963 to 1989) became available on the platform in November 2023, although we don't have any data as to which stories are showing, and which ones aren't. (One story that is certainly not available is An Unearthly Child due to ongoing rights issues.)
From all accounts, the content seems to match that of other platforms, such as BritBox and Roku, being regular episodes and animated reconstructions; this doesn't include stories that exist now as a combination of live action and animation (such as The Tenth Planet, The Moonbase).
