In 2021, Porto/Post/Doc returned to the cinemas of downtown Porto with a renewed desire to reunite films, audiences, and guests. Over eleven days, the festival presented its four competitions, several thematic sections, and discussion spaces such as the Fórum do Real and the Call to Action programme.

In response to the climate crisis, the festival took a clear stance through the programme "Ideas to Postpone the End of the World", conceived during the pandemic in collaboration with Indigenous leader Ailton Krenak. Developed between Porto and the Krenak territory, this cycle addressed urgent environmental and social issues.

In addition to its regular venues — Rivoli, Passos Manuel, the Planetarium, and Casa Comum — the festival also occupied the recently reopened Sala Estúdio Perpétuo, dedicated to new Portuguese documentary and children's screenings, and the Coliseu AGEAS, which hosted the closing night with the audiovisual installation "As Filhas do Fogo" by Pedro Costa and Músicos do Tejo.

The festival opened with a cine-concert of "Maria do Mar" by Leitão de Barros, featuring a score by Bernardo Sassetti, performed by Pedro Burmester and the Lisbon Sinfonietta Orchestra.

Among the international highlights were works by Basir Mahmood and Theo Anthony, noted for their originality and creative strength.

The festival fostered both informal and professional encounters among filmmakers, audiences, journalists, and activists, around films that addressed contemporary issues and showcased the diversity of Portuguese and international cinema. The Call to Action discussions encouraged reflection on community, identity, and resistance.