60-year-old Diana Nyad (Annette Bening) repeatedly attempts to beat the odds by swimming non-stop for 110 miles from Cuba to Florida after failing to swim the same trek when she was 28. Bonnie Stoll (Jodie Foster), her best friend, serves as her coach while John Bartlett (Rhys Ifans) gets hired as her navigator who captains her support boat.

      Based on the memoir by Diana Nyad, the screenplay by Julia Cox follows a conventional underdog sports drama formula, but it's nonetheless an inspirational and moving story even though it tries a little too hard to tug at your heartstrings. Diana remains determined from start to finish to never give up trying to complete the 110-mile swim between Cuba and Florida which no one has accomplished before. She has a tough time finding sponsors because of her age, but eventually she finds one. Her best friend, Bonnie, wants what's best for her and remains a truly good friend to her despite some rough patches along the way in their relationship. Cox does a mediocre job of incorporating exposition, though. There's too little information about how Diana and Bonnie became friends, although Diana explains to a stranger at a party that they had briefly dated years ago. Meanwhile, Diana has flashbacks to a traumatic event from her childhood which she hasn't overcome yet, but what precisely happened back then isn't revealed until much later in the film. By the end, though, it's still underexplored and sugar-coated in favor of keeping the film more light and upbeat. What makes Diana compelling as a character and more human concurrently is that she's somewhat of a narcissist with a huge ego who loves to talk about herself and has a one-track mind. However, she's not a malignant narcissist because she shows that she's introspective when she calls John to offer him a genuine apology while acknowledging her actions that hurt him. She doesn't give him an excuse for how she treated him nor does she gaslight him which is admirable.

      Screenwriter Julia Cox should be commended for also humanizing Bonnie. There's a particularly poignant scene when Bonnie bluntly tells Diana that she hasn't figured out yet what dreams she wants to fulfill for herself while making it clear that she's the only one who gets to determine what those dreams are and what she wants out of life. No one else gets to decide that for her, so for Bonnie to stand up for herself like that in front of Diana makes her brave and emotionally mature---perhaps more emotionally mature than Diana. The swimming scenes are exciting with a few thrilling and surprisingly scary moments involving sharks and jellyfish. It's also worth mentioning the effective use of comic relief at the just the right moments which prevent the film from being a dry, pedestrian biopic. The third act, which can be seen from a mile away, is somewhat schmaltzy, though, with preachy, on-the-nose messages about never giving up. If only the filmmakers could'e trusted the audience's intelligence more to allow them to interpret the film's message on their own rather than to have it spoon-fed to them.

      Annette Bening and Jodie Foster give terrific performances that help to keep the film afloat. They're wonderful together and have great chemistry. The emotional depth comes from their performances more than from the screenplay. It's refreshing to see Rhys Ifans play against type in a serious role which he brings to life with his warm and tender performance. There are pacing issues, though. During the first hour, the pace moves too quickly before slowing down a little and then picking up again. The scenes with Diana swimming are intense, but go on for too long. At a running time of 2 hours, Nyad is a heartfelt, empowering and inspirational emotional journey anchored by Annette Bening and Jodie Foster's bravura performances.