River Song has met more incarnations of the Doctor than most characters on Doctor Who movie followed in 1996, then the series returned in 2005 and has been running ever since. The main character of Doctor Who is the eponymous Doctor, who, when near death, can completely change their physical body and take on a new appearance in a process known as regeneration. This is a feature (mostly) unique to the Doctor's alien species of Time Lords from Gallifrey.
River Song made her debut in Doctor Who in 2008 as a mysterious woman who has met the Doctor before, although he has not met her. She dies at the end of her two-part premiere, realizing that though this was the first time the Doctor met her, it was the last time she saw him. Younger versions of River went on to appear in Doctor Who for the next several years and her backstory was further explained. Not only is River Song the Doctor's wife, but she is the child of companions Amy Pond and Rory Williams. She was conceived on the time-traveling TARDIS so was imbued with some Time Lord traits, including extended life and regeneration. Her given name is Melody Pond, but she goes by the name River Song in her third incarnation, portrayed by Alex Kingston.
Melody/River's timeline can get confusing, even for her. She keeps a TARDIS-inspired journal to keep track of her life and all her encounters with the Doctor. This includes descriptions of every incarnation of the Doctor she has met. With such a long life, it's no surprise River has met several versions of the time traveler; here's each one.
Tenth Doctor
River Song's first appearance to the Doctor and the audience is in Doctor Who season 4, episode 8, "Silence in the Library." The two-part story continues in season 4, episode 9, "Forest of the Dead," in which River sacrifices herself to save the people trapped in the library. In these episodes, River Song interacts with the Tenth Doctor (David Tennant) and his companion Donna Noble (Catherine Tate). These are River's only on-screen interactions with Ten, but she did meet him again in a handful of Big Finish Productions audio plays. They adventure together in three stories in the anthology The Tenth Doctor and River Song. River also encounters Ten in the audio plays A Brave New World and The First Son, plus the 2022 video game Lost in Time. The latter actually takes place before "Silence in the Library," but River erases the Doctor's memory of her to maintain the timeline.
Eleventh Doctor
River Song seems to have encountered the Eleventh Doctor (Matt Smith) more than any other incarnation, and this is the Doctor she actually marries. Their first on-screen adventure together is Doctor Who season 5, episode 4, "The Time of Angels" and its second part, "Flesh and Stone." This is also the first time companion Amy Pond (Karen Gillan) meets River, who she later learns is her daughter. Moving backward through her timeline, River next appears with Eleven in season 5, episode 12, "The Pandorica Opens" and episode 13, "The Big Bang." River and the Eleventh Doctor also appear together in the video game The Eternity Clock set during this season.
Doctor Who season 6 largely revolves around River Song, telling the story of her birth and then kidnapping by Madame Kovarian to be trained to kill the Doctor. She goes through two regenerations, then finally gets married to the Eleventh Doctor. This story unravels out of order starting with season 6, episode 1, "The Impossible Astronaut," and ending with season 6, episode 13, "The Wedding of River Song." The season 6 DVD box set also included a series of five shorts, two of which featured River Song: "First Night" and "Last Night."
River sees the Eleventh Doctor and her parents again in Doctor Who season 7, episode 5, "The Angels Take Manhattan." This is the last time, possibly ever, she sees her parents and the Eleventh Doctor before her death. Her last interaction with the Eleventh Doctor is in season 7, episode 13, "The Name of the Doctor." Her consciousness, saved by David Tennant's Tenth Doctor after her death in "Forest of the Dead" communicates telepathically with companion Clara and other friends of the Doctor. She has one final conversation from the afterlife with the Doctor before fading away, although her consciousness is still presumably saved in the library. This is River's final chronological appearance.
Twelfth Doctor
River meets the Twelfth Doctor (Peter Capaldi) for the first time in the 2015 Christmas special, "The Husbands of River Song." She doesn't recognize this incarnation of the Doctor, so he remains incognito for most of the episode, before finally revealing that he's the Doctor. At the end of the episode, the Doctor takes her to the Singing Towers of Darillium, which she had mentioned visiting with the Doctor before her death in "Forest of the Dead." The Doctor gifts her a sonic screwdriver before they spend their last night on Darillium (which is equal to twenty-four Earth years) together. This is the last on-screen appearance of River Song in Doctor Who (so far). River also sends a message to the Twelfth Doctor during the events of the video game Lost in Time, but they don't meet face-to-face.
Eighth Doctor
River Song almost meets the Eighth Doctor (Paul McGann) in season 1 of The Diary of River Song audio play series. She avoids meeting him directly by only communicating with him over a distorted radio transmission. In several "Doom Coalition" stories, part of The Eighth Doctor Adventures series, she once again encounters the Eighth Doctor, continuing to avoid directly interacting with him. She uses a psychic wimple to disguise herself as a nun with a different face when she does meet him. In "Doom Coalition 4," they connect via psychic link while the Eighth Doctor is in the Time Vortex, but he loses this memory. River and Doctor Who's Eight finally meet face-to-real-face in "Lies in Ruins," part of The Legacy of Time anthology. In The Eternity Clock, River notes in her diary that she likes the Eighth Doctor's TARDIS.
Thirteenth Doctor
River's only known encounter with her "occasional wife," the Thirteenth Doctor (Jodie Whittaker), was in the 2020 short story "The Guide to the Dark Times" from Doctor Who The Official Annual 2021. Thirteen runs into River after the latter rescues the Black Scrolls of Rassilon from Gallifrey. Thirteen then writes an introduction to a newspaper article by River about the "Dark Times" as described in the scrolls. It's not clear when this meeting takes place in River's timeline.
Other Incarnations
River's diary in The Eternity Clock reveals she has had run-ins with the first nine Doctors, too, though details are scarce. She saw the First Doctor at 76 Totter's Lane, where he was keeping the TARDIS in the very first episode of Doctor Who, "An Unearthly Child." She noted that she didn't particularly like the Second Doctor. She got along with the Third Doctor and thinks the Sixth Doctor's hair was an attempt to copy hers. She noted the Ninth Doctor was sensitive to mentions of the Great Time War. River has also met the Fourth, Fifth, Sixth, and Seventh Doctors during The Diary of River Song, but she always manages to keep her identity under wraps.
River has pictures of the first several incarnations of the Doctor, including a photo of the War Doctor, who fell between Eight and Nine but isn't included in the official count. River didn't have photos of any Doctor after Eleven, but since she did meet Twelve and Thirteen, it's possible she will meet future Doctors, too, either on-screen in Doctor Who or in audio plays, games, and books.