Star Trek is full of incredible time travel episodes, spanning across every series and the movie franchise. As one of the quintessential science fiction concepts, time travel was incorporated into Star Trek from its very earliest days, showing up as early as Star Trek: The Original Series season 1, episode 4, “The Naked Time.” From there, the franchise took the concept and ran with it, including time travel or elements of it into countless episodes and making it the focal point of some of the best storylines across the series.
To date, every Star Trek TV show has included at least one time-travel episode. These episodes have mainly shown characters journeying to the past, but some storylines have incorporated the future as well. There have also been smaller more self-contained episodes that deal with time loops or time slips, where a certain character is thrown out of time unexpectedly. Some of Star Trek‘s most iconic episodes feature time travel, but given how many storylines related to it there are in the franchise, some episodes about it are undeniably better than others.
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20 Such Sweet Sorrow Part 2
Star Trek: Discovery season 2, episode 14
Although the main focus of Star Trek: Discovery‘s season 2 finale, “Such Sweet Sorrow Parts I&II” wasn’t exclusively about time travel, the episode ended with the USS Discovery and her crew traveling 930 years into the future to defeat Control. Much of Discovery season 2 also revolved around the theme of time travel, as Michael Burnham (Sonequa Martin-Green) worked to uncover the identity of the Red Angel. “Such Sweet Sorrow Part II” was a significant turning point in Discovery‘s story trajectory, and the scene where the ship traveled to the future was incredibly moving, but objectively, time travel only made up a small portion of the episode.
19 Star Trek (2009)
J.J. Abrams’ first Star Trek Reboot movie
J.J Abrams’ reboot film series began in 2009 with Star Trek, which quickly established the Kelvin Timeline, an alternate reality created when Ambassador Spock (Leonard Nimoy) traveled back in time with the film’s villain Nero (Eric Bana) through a black hole. Star Trek (2009) was a solid addition to the Star Trek movie series but rewrote franchise history and remains somewhat controversial in its attempt to reimagine Captain Kirk (Chris Pine) and the crew of the USS Enterprise. The time-travel aspect of the film also dealt more with alternate realities and was a comparably small part of the overall plot.
18 Assignment: Earth
Star Trek: The Original Series season 2, episode 26
Star Trek: The Original Series was full of great time travel episodes, and while season 2, episode 26, “Assignment: Earth” wasn’t the greatest, the episode is still memorable for a few reasons. “Assignment: Earth” was originally intended to be a backdoor pilot for a Star Trek spinoff series of the same name, but this never came to fruition since the plot failed to generate much interest. Still, the character of Gary Seven (Robert Lansing) established the Supervisors, who would become important in Star Trek: Picard season 2, and the episode was the first significant TV role for actress Terri Garr.
17 Magic To Make The Sanest Man Go Mad
Star Trek: Discovery season 1, episode 7
Combining time-travel tropes with the return of a classic Star Trek character, Discovery delivered a fun bottle episode with season 1, episode 7, “Magic to Make the Sanest Man Go Mad.” After infiltrating the USS Discovery, Harry Mudd (Rainn Wilson) initiated a time loop, continually blowing up the ship and killing the crew to learn the secrets of Discovery’s spore drive. The episode was significant for establishing more of Mudd’s backstory, but the plot isn’t as impactful when compared to similar time-loop episodes from other series.
16 Cause And Effect
Star Trek: The Next Generation season 5, episode 18
Star Trek: The Next Generation‘s season 5, episode 18, “Cause and Effect” featured the crew of the USS Enterprise-D caught in their own version of Groundhog Day, as the ship repeatedly exploded after colliding with another Starfleet vessel from the past, the USS Bozeman. The Bozeman’s crew provided TNG with a special cameo in the form of Captain Morgan Bateson (Kelsey Grammer), and “Cause and Effect” featured two examples of time travel in one storyline. However, when compared to other TNG time-travel episodes, “Cause and Effects” ranks relatively low in terms of significance.
15 Trials And Tribble-ations
Star Trek: Deep Space Nine season 5, episode 6
One of the most entertaining episodes of Star Trek: Deep Space Nine, “Trials and Tribble-ations,” dealt with DS9‘s crew being thrown back in time to the era of Star Trek: TOS, during the events of the episode, “The Trouble with Tribbles.” Archival footage from the classic TOS episode was used in conjunction with the new scenes filmed, providing “Trials and Tribble-ations” with some seriously memorable moments like Captain Sisko (Avery Brooks) meeting Captain Kirk. The episode was amusing and a great crossover between the two series, but was mostly a light and fun romp, lacking the emotional impact of other Star Trek time travel stories.
14 Time’s Arrow Parts I&II
Star Trek: The Next Generation season 5, episode 26, & season 6, episode 1
“Time’s Arrow” continues to be one of the more famous two-part episodes of Star Trek: TNG. During the episode, the discovery of Data’s (Brent Spiner) severed head in a San Francisco cave set off a chain of events that led the crew of the Enterprise-D to become stuck back in time in 1893. The now-infamous appearance of Mark Twain (Jerry Hardin) arguably kicked off the franchise’s love affair with Star Trek‘s favorite author, and the exploration of Guinan (Whoopi Goldberg) and Captain Picard’s backstory was a welcome addition. “Time’s Arrow” is not the most important time travel story in TNG, but it would be a mistake to overlook it.
13 All Our Yesterdays
Star Trek: The Original Series season 3, episode 23
“All Our Yesterdays” was the second-to-last episode of TOS and a fascinating time travel story. While visiting a planet to warn its residents of an impending disaster, Kirk, Spock, and Dr. McCoy (DeForest Kelley) accidentally ended up in different eras in the planet’s past, with Kirk in the equivalent of 17th-century England and Spock and McCoy banished to the planet’s ice age. “All Our Yesterdays” included some great guest stars like Mariette Hartley, and is one of TOS‘s better time travel episodes overall, although not as well-remembered as episodes from other series.
12 Storm Front Parts I&II
Star Trek: Enterprise season 4, episodes 1 & 2
As a culmination of several storylines on Star Trek: Enterprise, “Storm Front Part I&II” was a huge episode for the series that dealt with a range of subjects. After being pulled back in time by Temporal Agent Daniels (Matt Winston) to an alternate WWII-era Earth, the crew of NX-01 Enterprise were tasked with helping stop the Temporal Cold War and the infiltration of the Na’kuhl, who had altered the timeline and allied themselves with the Nazis. The Temporal Cold War and well as the ongoing Suliban storyline came together in “Storm Front,” and the episode resolved both well, wrapping up some major plot points for Enterprise in the process.
11 Star Trek: First Contact
The second movie in the Star Trek: TNG film franchise
Star Trek: First Contact is widely considered the best of the TNG movies, and featured an engaging time travel story involving the Borg and the birth of the Federation. In the film, Picard and crew traveled back in time to 2063 to stop the Borg Queen (Alice Krige) from interfering with Zefram Cochrane’s (James Cromwell) first warp flight. The introduction of the Borg Queen and the depiction of humanity’s first contact with the Vulcans were major additions to Star Trek lore, and the exploration of Picard’s ongoing trauma from his Borg assimilation added some wonderful emotional weight to the movie’s plot.
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10 Little Green Men
Star Trek: Deep Space Nine season 4, episode 8
Quark (Armin Shimmerman), Rom (Max Grodénchik), and Nog (Aron Eisenberg) stole the show in DS9‘s “Little Green Men.” After a shuttle malfunction, the three Ferengi were thrown back in time to 1947, crash landing in Roswell, New Mexico on Earth, and were subsequently captured by the US government. The episode’s humor and the popularity and talent of DS9‘s Ferengi characters combined to make a winner, and although “Little Green Men” didn’t have a larger impact on the series or franchise as a whole, it is an undeniably well-executed episode.
9 Future’s End Parts I&II
Star Trek: Voyager season 3, episodes 8 & 9
Star Trek: Voyager dealt with time travel a lot, and one of the most memorable episodes was the two-part “Future’s End” which saw Voyager’s crew ending up in 1990s Los Angeles after being pulled through a time rift. Once there, Captain Janeway (Kate Mulgrew) and crew found themselves doing battle with Henry Starling (Ed Begley Jr.), a billionaire tech mogul armed with dangerous 29th-century technology. Guest stars like Begley Jr. and Sarah Silverman elevated the episode considerably, and Voyager managed to balance the complicated overarching plotlines quite well.
8 Past Tense Parts I&II
Star Trek: Deep Space Nine season 3, episodes 11 & 12
Lauded as one of Deep Space Nine‘s best episodes, “Past Tense Part I&II” found Sisko, Dr. Bashir (Alexander Siddig), and Jadzia Dax (Terry Farrell) accidentally time-traveling to Earth 2024 after a transporter accident. There, the three were caught up in the political and social unrest of the time, altering the course of history when they were accidentally involved in the premature death of an important historical figure. The episode was highly praised when it first aired for its discussion and depiction of social and societal issues, many of which were relevant back when it aired and continue to be relevant today.
7 All Good Things…
Star Trek: The Next Generation season 7, episodes 25 & 26
The series finale of Star Trek: TNG, “All Good Things…” is often thought of as one of the best finales in the franchise. The storyline jumped between three different time periods, past, present, and future, following Captain Picard as his consciousness traveled between the three different points. The plot brought back the continuing storyline of Q’s (John de Lancie) test of humanity that was first introduced in TNG‘s pilot episode, providing a wonderfully cyclical ending to the series. Aside from being a great time-travel story, “All Good Things…” was a poignant and engaging farewell that was extremely well-received by audiences.
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6 Star Trek IV: The Voyage Home
The fourth movie in the Star Trek: TOS film franchise
The Voyage Home remains one of the best TOS films and a quintessential time travel story for the franchise. When a mysterious probe threatened Earth, the TOS crew traveled back in time to locate a pair of living humpback whales, bringing them to the future to answer the probe’s call. The hilarious hijinks of the Enterprise crew navigating 1980s San Francisco coupled with the surprisingly prescient conservationist message merged to create one of the most iconic Star Trek films of all time, featuring a slew of memorable moments such as Spock’s attempt to mind-meld with a whale or the botched mission to infiltrate a nuclear vessel in San Francisco Bay.
5 Tomorrow And Tomorrow And Tomorrow
Star Trek: Strange New Worlds season 2, episode 3
Star Trek: Strange New Worlds season 2 had many amazing episodes, but “Tomorrow and Tomorrow and Tomorrow” was one of the season’s best. During the episode, La’an Noonien-Singh (Christina Chong) found herself accidentally thrown back in time to 21st-century Toronto with an alternate timeline version of James T. Kirk (Paul Wesley). The episode involved some incredible twists and turns, including a cameo by the young version of La’an’s infamous ancestor Khan (Desmond Sivan). It was also a tour-de-force for La’an as a character and beautifully channeled one of Star Trek: TOS‘s all-time best episodes, “The City on the Edge of Forever.”
4 Timeless
Star Trek: Voyager season 5, episode 6
“Timeless” was the 100th episode of Star Trek: Voyager, and commemorated this milestone with a bang. After the USS Voyager crash-landed on an ice planet during an ill-fated attempt to return to the Alpha Quadrant, the ship’s only survivors, Harry Kim (Garrett Wang) and Chakotay (Robert Beltran) worked for 15 years to figure out a way to send a message back in time warning Voyager about the crash. The episode’s standout performance is Wang’s portrayal of the older Harry Kim, but the action-packed plot and a surprise cameo by Star Trek: TNG fan-favorite Geordi La Forge (LeVar Burton) cemented it as one of Voyager‘s best.
3 The Visitor
Star Trek: Deep Space Nine season 4, episode 3
One of the strongest aspects of Star Trek: DS9 was the relationship between Captain Sisko and his son, Jake (Cirroc Lofton), something that “The Visitor” explored masterfully. The episode was told from the point of view of an older Jake Sisko recounting the story of how his father became unstuck in time during an accident on the USS Defiant and had been appearing in his life at random moments ever since. The emotional gut punch of Jake’s self-destruction as a result of trying to save his father, coupled with the unintentional foreshadowing of Sisko’s ending in DS9‘s finale created one of the most moving and well-crafted episodes of the series.
2 Yesterday’s Enterprise
Star Trek: The Next Generation season 3, episode 15
“Yesterday’s Enterprise” is still considered one of the best episodes of Star Trek: TNG, and involved a fascinating time-travel story. The appearance of the USS Enterprise-C from a tear in spacetime caused a drastic timeline shift, thrusting the Enterprise-D crew into a much harsher alternate reality where Starfleet was at war with the Klingons. “Yesterday’s Enterprise” featured the first return of Tasha Yar (Denise Crosby) who had died at the end of season 1, and is also the only Star Trek project to ever explore the USS Enterprise’s history between Captain Kirk and Captain Picard, introducing the franchise’s true first female captain before Janeway, Captain Rachel Garrett (Tricia O’Neil).
1 The City On The Edge Of Forever
Star Trek: The Original Series season 1, episode 28
Often considered one of the best episodes of the entire Star Trek franchise, “The City on the Edge of Forever” is undoubtedly also the franchise’s top time-travel episode. After a drug-addled Dr. McCoy (DeForest Kelley) traveled back in time through the Guardian of Forever, Captain Kirk and Spock followed McCoy back in time to 1930s New York City, where Kirk fell in love with a woman named Edith Keeler (Joan Collins). In a slew of romances, Kirk’s relationship with Keeler is still thought of as the character’s most iconic, and the episode’s beautifully crafted storyline arguably laid the groundwork for every other time travel episode that came after it.
