Free with ads
Many Malayalam films, especially older ones, stream free with ads. Amazon MX Player carries a large free library in India, and several Malayalam studios put full films on their official YouTube channels. Abroad, Tubi and Pluto TV carry free titles too.
Included in your plan
Many mobile and broadband plans in India include JioHotstar, Prime Video, ZEE5 or SonyLIV in the price, so a big library may already be yours.
How Watch Now shows them
Press Watch Now on any title and the list for your country shows the free options whenever there are some. The Malayalam Classics are the likeliest.
New releases
New films usually start on a subscription app and reach the free ones later. Add them to My List and check again.
