It was confirmed at Comic-Con that when Star Trek: Discovery returns, the show will be thrust 1,000 years into the future. WAY past where any Star Trek series has ever gone before. But time travel is a Trek staple, and has some of the best episodes of the franchise have dealt with crazy temporal adventures. Here are our picks for the top ten Star Trek time travel episodes from the franchise’s 53 year run.
Note: TOS is official Trek-shorthand for the The Original Series, TNG is The Next Generation, DS9 is Deep Space Nine, while VOY is Voyager.
10. “All Our Yesterdays” (TOS)
This last season of TOS isn’t great, buy this one is a stand out. After the Enterprise encounters a planet on the brink of dying due to an imminent nova, they discover that its inhabitants have all traveled into their world’s past to save themselves from annihilation. Spock accidentally travels into that world’s Ice Age thousands of years in the past — an era when Vulcans were very much NOT in control of their emotions. And these new emotions are made even more complicated when he meets a young woman who sparks his human feelings to awaken.
9. “Yesteryear” (TAS)
TAS only ran two seasons and doesn’t get the love it deserves, but this episode is widely considered a standout. A sequel of sorts to the original series’ “City on the Edge of Forever,” this chapter finds Spock time travelling into his own childhood on Vulcan. Posing as his own distant cousin, adult Spock saves his younger self from death, ensuring his own future timeline remains intact. Unlike any other TAS episode, elements of this one are referenced in Spock’s TNG appearance “Unification,” as well as JJ Abrams’ 2009 big screen reboot.
8. “Year of Hell” (VOY)
This two parter aired in Voyager’s fourth season, and put Janeway and her lost crew through the ringer in ways they never had before. Voyager finds itself the undergoing several changes to its timeline, as an alien ship commander attempts to re-sequence history in a way that only benefit him. Sometimes all the time shenanigans are pretty confusing in this one, but it was still one of the more inventive Voyager episodes. If it were made today, this two parter would no doubt constitute a whole season’s worth of episodes.
7. “Little Green Men” (DS9)
The alleged 1947 Roswell, New Mexico UFO incident has sparked many, many sci-fi stories. But one of the most creative riffs on the Roswell legend came in this fourth season episode of DS9. In this episode, the show’s resident Ferengis Quark, Rom and Nog are accidentally thrown back in time on the way to Earth and crash in (you guessed it) Roswell. The greedy and capitalistic Ferengi find themselves relating far more to the less than perfect humans of the 20th century than their squeaky clean future counterparts. Mostly played for laughs, this is still a super inventive and delightful episode.
6. “Tomorrow is Yesterday” (TOS)
TOS did the time travel thing a lot, probably due to the fact that it helped save on budget. One of the earliest examples was this episode, which finds the Enterprise hurled hundreds of years back to the ’60s. There, they encounter an US Air Force pilot and beam him aboard the ship to save him from the destruction of his aircraft. Realizing they can’t send him back now due to his knowledge of the future, this creates an ethical conundrum for Kirk, the first time in Star Trek history we get an inkling of the Federation’s strict rules about time travel.
5. “Endgame” (VOY)
Although not as great as the TNG finale, the Voyager finale episode also uses time travel to great effect. In this chapter, Kate Mulgrew plays a much older Admiral Janeway, decades into that character’s the future. It’s revealed that it took Janeway 23 years to bring her ship back home to Earth from being lost, a journey which cost the lives of many over the years. Unwilling to accept her present, Janeway travels back in time and concocts a plan to bring her ship home much sooner than it originally did, thus meeting her younger self in the process. All this cool time travel stuff, plus the Borg too! Not a bad way to go out.
4. “All Good Things” (TNG)
The TNG series finale, “All Good Things” isn’t just the best of all the Star Trek series finales, but arguably one of the best series finales of any show ever (and a huge influence on Avengers: Endgame.) This two hour final chapter has Q shuffling Picard backwards in time to solve a universe ending threat. At first, Picard finds himself back in the events of the show’s pilot episode, and then jumps 25 years in the future, thus giving fans a glimpse into the future lives of the Enterprise crew. The perfect mix of high concept sci-fi and emotional character growth, “All Good Things” remains the gold standard for series finales, and a great time travel yarn.
3. “Trials and Tribble-Ations” (DS9)
“The Trouble with Tribbles” is one of the most beloved episodes of TOS. And for Star Trek’s 30th Anniversary, the producers of DS9 decided to pay homage to the episode by having their characters actually travel back in time into the original classic episode itself. This was all accomplished using then-cutting edge technology, and recreating the original 60s sets and splicing in the DS9 crew right alongside Shatner and Nimoy. The whole episode is essentially a light-hearted romp, but it’s pulled off perfectly. And remains pure joy to watch for Trek fans decades later.
2. “Yesterday’s Enterprise” (TNG)
Talk about an episode that has everything. This third season TNG ep fills in gaps in Trek history, gives us an alternate universe version of the Enterprise crew, AND gives a former cast member (Denise Crosby) a proper farewell. When the Enterprise-D encounters their predecessor the Enterprise-C travelling 22 years into the future escaping destruction, the current timeline is changed into one of endless war. Does Picard send the previous Enterprise back in time to certain death, ensuring the “proper” timeline is restored, or is keeping them alive potentially dooming the Federation in the present? All this, plus Worf laughs for the first time in the series!
1. “The City on the Edge of Forever” (TOS)
Not only the best time travel episode of Star Trek, but almost universally regarded as the best episode of Trek, period. This late first season episode was written by legendary author Harlan Ellison. It tells the story of what happens when Kirk and his crew encounter the ancient and powerful Guardian of Forever, an alien construct which can transport beings back into any time period. But when a temporarily insane McCoy travels back to the ’30s, he does something that fundamentally destroy’s Earth’s future. Kirk must follow him back to Depression-era New York and undo what McCoy did, and in doing so he meets the love of his life. Heartbreaking and brilliant, this is Star Trek at its very best.