While Benicio Del Toro's character is frequently silent in the movie, he initially had more lines. "In the original script, the character explained his background several times to Kate," Del Toro said. "And that gave me information about who this guy was, but it felt a little stiff to have someone you just met fifteen minutes ago suddenly telling you what happened to him and who he is." Working with director Denis Villeneuve, Del Toro began cutting some of his dialogue to preserve the mystery of who his character is; Villeneuve estimated they cut 90% of what Del Toro was originally intended to say by screenwriter Taylor Sheridan. Like Del Toro, Villeneuve saw power in stripping the character down to a brooding silence, stating that dialogue belongs to plays and "movies are about movement, character, and presence, and Benicio had all that."
Having just completed Everest (2015), an exhausted Josh Brolin turned down this film. Cinematographer Sir Roger Deakins sent him an email imploring him to join the project. Since it was so uncharacteristic of Deakins to take this stand, Brolin changed his mind.
The border crossing scene was one of the most complicated parts of the production. It took so long to shoot that a full scale replica of the Juarez border crossing was built. Shooting at the real location would have required days of road closures, which would not have been practical.
When discussing the score with composer Jóhann Jóhannsson, director Denis Villeneuve said he wanted the sound of a threat. The one film Villeneuve used as a comparison was director Steven Spielberg's Jaws (1975) (music by: John Williams).
Actress Emily Blunt (Kate Macer) was so sick from food poisoning whilst filming in Mexico that she required IV fluids between takes just to make it through her scenes.