According to Sir Kenneth Branagh, roughly thirty Dunkirk survivors, who were in their mid-90s, attended the premiere in London, England. When asked about the movie, they felt that it accurately captured the event, but that the soundtrack was louder than the actual bombardment, a comment that greatly amused writer, producer, and director Sir Christopher Nolan.
After first-hand accounts of the Dunkirk evacuation revealed to writer, producer, and director Sir Christopher Nolan how young and inexperienced the soldiers were, he decided to cast young and unknown actors for the beach setting.
Writer, producer, and director Sir Christopher Nolan, along with his wife, producer Dame Emma Thomas, and a friend, made the crossing from England to Dunkirk on a boat, the way the civilians would have done during the original evacuation. Nolan said it took 19 hours because of sea conditions.
The end credits state that twelve of the original little ships that participated in the Dunkirk evacuation appeared in the movie, re-enacting their presence in 1940.
The scene in which Farrier's (Tom Hardy's) Spitfire lands on Dunkirk beach was real, done on-location with an actual Spitfire in flight, and was the first time a plane landed on that beach since 1940. After the scene was completed, however, the Spitfire became stuck in the sand. There was subsequently a frantic rush to get the valuable Spitfire off of the beach before the incoming tide could damage it.
Michael Caine: As the voice of the Royal Air Force flight leader. This is the seventh collaboration between Sir Christopher Nolan and Caine, after Batman Begins (2005), The Prestige (2006), Il cavaliere oscuro (2008), Inception (2010), Il cavaliere oscuro - Il ritorno (2012), and Interstellar (2014). Caine previously portrayed an RAF pilot in I lunghi giorni delle aquile (1969).
John Nolan: Sir Christopher Nolan's uncle appears as a blind man. As of 2025, this is John's last feature film role.