Star Fox, Star Fox 64 and Star Fox Adventures are the only Star Fox titles to provide official ages for the main characters, primarily within their Japanese ancillary material. In the Original Soundtrack box released for the first game, Fox, Falco, Peppy and Slippy are said to be 25, 28, 36 and 19 respectively. Star Fox 64, being a remake of the first game, would retcon these ages and make Fox 18, Falco 19, Peppy 41 and Slippy 18.

The "Farewell Beloved Falco" midquel manga, which is set right in the middle of the eight years between Star Fox 64 and Star Fox Adventures, also gives the original Star Fox crew ages, with Fox now being 22, Slippy 22, Falco 23, and Peppy 45.

Star Fox Adventures takes place eight years after Star Fox 64, which means that Fox is now 26, Falco 27, Peppy 49 and Slippy 26. Japanese Star Fox Adventures ancillary material also reveals Krystal's age to be 19, making her distinctly the only Star Fox character outside of the original four Star Fox members to have a known age. Going by this, she would be 11 and 15 years old during the events of Star Fox 64 and Farewell Beloved Falco, respectively.

After Adventures' release, Nintendo, specifically Takaya Imamura, made a deliberate decision for future Star Fox games to not provide any official age numbers for any of the characters. However, Star Fox Assault officially is said to take place only year after the events of Star Fox Adventures, so this would make Fox 27, Falco 28, Peppy 50, Slippy 27, and Krystal 20. Similarly, according to Takaya Imamura in a 2007 interview, Star Fox Command takes place 2-3 years after Assault, which would make Fox 29-30, Falco 30-31, Peppy 52-53, Slippy 29-30, and Krystal 22-23.

Although Wolf O'Donnell has never had any age officially listed for him, Takaya Imamura implied on Twitter that he is within the same generation of Peppy and James.