According to director John Boorman's audio-commentary, Geoffrey Rush smokes whereas Pierce Brosnan doesn't whilst Brosnan's character Osnard smokes and Rush's character Harry doesn't. So in the breaks between scenes, often Brosnan would put his cigarette out at the same time Rush would light up.
The DVD shows the film's alternate ending where Harry Pendel (Geoffrey Rush) shoots Andy Osnard (Pierce Brosnan). The studio didn't like this downbeat heavy-handed ending so the ending in the film has Osnard live, seen on a plane leaving Panama and flirting with an air hostess.
In John le Carré's 'The Tailor of Panama' novel, spy Andrew Osnard is twenty-seven years of age. The part had to be adapted as Brosnan was about twenty years older than this.
Savile Row, a street famous for its tailoring establishments in central London and mentioned many times in the film, is misspelled "Saville" on the computer screen that Osnard scans on the flight.
When Andy is dancing with Francesca for the first time at the outdoor bar/restaurant, her sunglasses at one point are almost completely falling off the back of her head; when the shot moves to close up, they are back on the top of her head.