If you prefer reading the dialogue rather than having on-screen text, the full Donnie Darko screenplay is available online via Daily Script. Donnie Darko (2001) - DVD Movie Guide
If you have a digital file (like an .MKV or .MP4) and need an external subtitle file (.SRT), several reputable repositories host them. Note that you may need to choose a file that matches your specific version (Theatrical vs. Director’s Cut) to ensure the timing is correct.
The 4K UHD release includes English SDH (Subtitles for the Deaf and Hard-of-Hearing) for both the theatrical and director's cuts. Donnie Darko subtitles English
Finding English subtitles for Donnie Darko is straightforward, whether you're watching a physical copy or looking to download them for a digital file. Official Subtitles (Physical & Streaming)
If you own the movie on physical media or are streaming it, English subtitles are typically built-in. If you prefer reading the dialogue rather than
: A massive community-driven site that is great for finding subtitles for older or rare editions.
: A site specifically dedicated to high-quality English language tracks. Script for Reference Director’s Cut) to ensure the timing is correct
Standard DVD versions also feature English and Spanish subtitles.