↑ The inclusion of Sara Kingdom as a companion varies; e.g. she does not appear on the BBC website list of companions.
↑ Jamie is played by Hamish Wilson in parts of The Mind Robber episodes 2 and 3, while Frazer Hines was suffering from chickenpox.
↑ Jamie returns to his own time in The War Games, but later appears in the Sixth Doctor-era story The Two Doctors, again as the Second Doctor's companion.
↑ Sarah continues to travel with the Doctor following his regeneration in Planet of the Spiders, and after her later departure from the series serves as the Third Doctor's companion once more in The Five Doctors.
↑ This first incarnation of K-9 returns in the independent spin-off series K-9, regenerating into a newer form.
↑ A further model of K-9, "Mark III", features in the pilot of K-9 and Company with Sarah Jane Smith, and Doctor Who episode "School Reunion" with the Tenth Doctor and Sarah Jane. Killed and replaced by K-9 Mark IV in the latter episode, he subsequently appears irregularly in The Sarah Jane Adventures, and also the Doctor Who episode "Journey's End".
↑ Romana leaves the Doctor in Warriors' Gate, and subsequently reappears as the Fourth Doctor's companion in The Five Doctors (in footage from Shada).
↑ Tegan is left behind by the Doctor at the conclusion of Time-Flight but returns during the next serial Arc of Infinity, set around a year later in her relative time.
↑ Due to problems with the robotic prop, Kamelion was not featured in the five serials between his first and last stories. Planned scenes in The Awakening were cut and never broadcast.
↑ The series never establishes how Mel meets the Doctor, who first appears as part of the Doctor's future. Their first meeting is recounted in the Past Doctor Adventures novel Business Unusual and the Big Finish Productions audio-drama The Wrong Doctors. Note that the four adventures broadcast under the single title The Trial of a Time Lord are each counted as separate appearances in this table.
↑ Mel and Ace essentially swapped their men, with Mel flying off with the space smuggler Sabalom Glitz, while Ace took Mel's place beside the Doctor.
↑ Ace's fate was unknown past Survival as she does not appear in the following story, the 1996 film. Her post-companionship life was finally revealed in The Sarah Jane Adventures story, Death of the Doctor, in which she is said to have founded a philanthropy, A Charitable Earth (i.e., ACE), and to have raised millions. Sophie Aldred had been contracted by Russell T. Davies to return to the role of Ace in the second half of The Sarah Jane Adventures series 5, before Elisabeth Sladen's death cancelled the series.
↑ In the 2013 webcast "The Night of the Doctor", the Eighth Doctor makes reference to a number of his companions from the extensive Big Finish Productions audio series, but this list only concerns televised companions.
↑ Jack rejoins the Doctor in "Utopia" before departing in "Last of the Time Lords", but returns again for "The Stolen Earth" / "Journey's End". He also appears in The End of Time.
↑ Casey Dyer had previously played a young Mickey in "Father's Day".
↑ Mickey is introduced in "Rose" as Rose's boyfriend and recurs regularly before becoming a companion.
↑ Mickey departs in "The Age of Steel" and re-appears in "Army of Ghosts" / "Doomsday" before returning as a companion in "Journey's End". He also appears in The End of Time.
↑ After initially refusing to join the Doctor on his travels in "The Runaway Bride", Donna returns as a regular companion from "Partners in Crime". She also appears in The End of Time.
↑ Rachel Fewell portrays a younger Adelaide in flashback
↑ Wilf is introduced in "Voyage of the Damned", and recurs throughout series 4 as Donna's grandfather. He officially becomes a short-term companion (and is recognized as such by the Doctor) in The End of Time.
1 2 Amy and Rory are left by the Doctor in "The God Complex", but appear briefly in "Closing Time" and feature as companions again in "The Wedding of River Song". They appear in the final scene of "The Doctor, the Widow and the Wardrobe", before returning as companions from "Asylum of the Daleks".
↑ Rory is killed in "Cold Blood", but returns in "The Pandorica Opens" as an Auton duplicate before being restored to humanity and resuming his travels with the Doctor and Amy in "The Big Bang".
↑ Earlier incarnations of River Song (as Melody Pond) are played by Sydney Wade in "The Impossible Astronaut" / "Day of the Moon", and Maya Glace-Green and Nina Toussaint-White in "Let's Kill Hitler".
↑ River first appears alongside the Tenth Doctor in "Silence in the Library" / "Forest of the Dead", introduced as a companion from his relative future who calls the Doctor to her aid. Progressively younger versions of River subsequently summon the Eleventh Doctor in "The Time of Angels" / "Flesh and Stone" and "The Pandorica Opens" / "The Big Bang", before the future Doctor summons her to his death in "The Impossible Astronaut".
↑ River refuses the Doctor's offer to travel with her permanently in "Day of the Moon". She subsequently features as a companion in "A Good Man Goes to War", "Let's Kill Hitler" and "The Wedding of River Song", and also appears in "Closing Time". She later appears in "The Angels Take Manhattan" and "The Name of the Doctor".
↑ Coleman first appeared as Oswin Oswald in "Asylum of the Daleks", revealed in "The Name of the Doctor" to be one of multiple echoes of Clara distributed across time. In "The Snowmen", Coleman initially plays another echo of Clara, with her original iteration appearing briefly at the end of the episode. The latter Clara joins the Doctor permanently in "The Bells of Saint John".
↑ Clara dies in "Face the Raven" and appears only as an illusion in "Heaven Sent", before being temporarily rescued from death and appearing as a companion for the final time in "Hell Bent".
↑ Nardole first appears in "The Husbands of River Song" before appearing as a companion from "The Return of Doctor Mysterio".
