Every Star Trek series included episodes that dealt with time travel. Similar to episodes about holoprograms, time travel was a classic device used in the franchise to tell all types of stories. Whether our characters were traveling through time, being visited by people from the future, living through changed timelines, or dealing with something else time related, we’ve seen the characters of Star Trek thrust into some quite complex situations involving time.
Using this concept led to some of the best, and some of the worst, episodes in the series, so which stand apart from the rest? I decided to look through the many episodes involving time travel across all the TV series. Narrowing them to 15, here are my choices counting down to the best of the top Star Trek time travel episodes.
“Yesteryear,” The Animated Series Season 1
The Animated Series tells a number of good Star Trek stories and one of the best is “Yesteryear.” Featuring the Guardian of Forever first seen in The Original Series episode “City on the Edge of Forever,” the Enterprise is helping historians investigate Federation history using the Guardian. However when they return from a trip through the portal no one recognizes Spock and they discover an Andorian has replaced him as first officer. It turns out in this altered timeline Spock died as a child during a survival maturity test. Spock remembers that a cousin saved his life during that test and they figure out that his adult self is actually the cousin. Trying not to change anything else, Spock goes back in time, saves himself, and thus restores the timeline.
While the device of Spock turning out to be the cousin he remembers is a bit predictable, the episode is an interesting one as we learn more about Spock’s life as a child. It’s sad to see him being picked on by the Vulcan kids and to see him lose of his pet, I Chaya, which didn’t happen before. The conversations the adult Spock has with himself as a child do a good job of giving us more insight into his character and the struggles he’s had to deal with throughout his life.
“Relativity,” Voyager Season 5
In this episode, a device on Voyager causes temporal distortions that ultimately destroy the ship. Right before that happens though, Seven of Nine is taken out of time by a Federation time ship trying to find out who planted the temporal disruptor. It turns out she’s been recruited twice already, but this third time is the successful one. She goes back to when Voyager is under attack by the Kazon and is unable to find the weapon. Discovered, she’s apprehended by Janeway who questions her. Seven explains the situation and the two work together to find that it’s a future version of one of the men who recruited Seven doing this. Seven chases him to two more different points in Voyager’s timeline, ultimately meeting herself just before Voyager’s destruction, and saving the ship. Janeway is then recruited to help clean up the timeline due to Seven’s actions
It’s a fun episode that jumps around a lot in time and actually tries to deal with the problems those jumps cause. It never takes itself too seriously though thanks to some well-placed jokes. Of course it has one of those last minute solutions that occurs right at the end of the episode, but it’s a fun ride with some great scenes between Janeway and Seven as they work together to save the ship.
“Timeless,” Voyager Season 5
Harry Kim and Chakotay explore a frozen Voyager 15 years after it crashed, a disaster that killed everyone except them. They grab Seven of Nine’s body and the Doctor, and start to put a plan in motion to change the past. Voyager crashed due to Kim making a mistake in his calculations when the ship tried to use its quantum slipstream drive to get back to the Alpha Quadrant. The two have a plan to communicate with Seven in the past and send a new set of coordinates. While the first attempt seems to fail as a Captain La Forge tries to stop them, the second time their message works and disperses the slipstream before Voyager is destroyed.
The episode is a fascinating one in how it doesn’t involve people physically traveling in time, but sending messages instead in a unique way. We get to see them think about if it’s worth changing so much time, and consider the potential consequences. It also doesn’t even try to address the whole temporal paradox idea and how they could have received messages in the first place if that future never happened. At the end of this episode Janeway is right. It’s just not worth trying to figure it out!
“All Our Yesterdays,” The Original Series Season 3
When the Enterprise arrives at a planet about to be destroyed by a supernova, they find the whole population has disappeared. Eventually they discover that the planet’s inhabitants traveled back into their own history to live out their lives and escape the planet’s destruction. Unfortunately Spock and McCoy end up trapped in the Ice Age while Kirk is trapped in a different era during their investigation. As Kirk figures out how to escape and tries to rescue his friends, Spock begins to be impacted by the time travel and acts more like the ancient Vulcans. He falls in love with a woman they discover who was sent to that time, Zarabeth, and is emotional when he's forced to leave her in the end.
This episode offers a fresh take on the time travel idea. First it allows us a glimpse not into Earth’s past, but the past of a different planet entirely. Second, splitting the classic trio allows for some great moments between Spock and McCoy, and lets Kirk shine on his own. While it’s a little weird that none of the other time travel they’ve done has impacted Spock and McCoy doesn’t seem to change at all, it does give us another closer look at Spock and his often hidden emotions.
“Tomorrow is Yesterday,” The Original Series Season 1
Due to a black star, the Enterprise ends up in the 1960s. Noticing the ship in orbit, the Air Force sends fighter pilot John Christopher to take a look. To keep the ship from doing them any damage, Captain Kirk orders a tractor beam to lock onto the aircraft and it starts to destroy it. As a result, they beam Christopher on board to save him and this causes all sorts of complications. As Christopher learns about the ship and the future, Spock and Kirk at first decide he needs to stay on board and not return with the knowledge he’s gained which Christopher is not willing to accept. While Christopher’s attempt to escape is stopped, Spock announces that Christopher actually does need to return because his yet unborn son will play an important role in history. The rest of the episode sees the Enterprise trying to figure out how to return home and trying to recover all evidence collected of their appearance. At the end they’re able to return to the future and return Christopher without him remembering anything.
It’s interesting to see Christopher’s reaction to learning about the future and how the crew feels bad for his situation but is determined to do everything they can not to change the past. It has its serious and funny moments, like Kirk interacting with the military when he is captured on the base, and deals with the usual time travel issues. However even though it’s a rather straightforward time travel episode, that doesn’t take away from it being one of the more enjoyable and entertaining trips into the past for Star Trek.
“Little Green Men,” Deep Space Nine Season 4
This episode begins with Nog ready to head to Starfleet Academy. Right before he goes Quark receives a shuttle from his cousin Gaila, something his cousin has owed him for the last 10 years. When he, Rom, and Nog take it for a test run to the Academy, Quark stows away some kemocite to smuggle to Orion on the way back to the station. Luckily it comes in handy when it turns out Galia sabotaged the ship. Detonating the kemocite to save themselves, they wake up on Earth in 1947. It turns out they are being held by the military after crashing in Roswell. This leads to some hilarious moments as their universal translators malfunction for a while, making it hard for the humans and Ferengi to communicate. Of course Quark starts to think about how to make a profit out of the whole situation, but with the help of a stowed away Odo and two sympathetic humans, they’re able to escape and head back to their regular time.
If you want a humorous time travel episode, this one delivers. Focusing for the most part on non-main characters makes it particularly compelling too as the dynamic between the three Ferengi is explored more as they deal with this situation and try not to change too much of the past.
“Time’s Arrow,” The Next Generation Season 5 and Season 6
The Enterprise returns to Earth when it is discovered that aliens visited the past and the evidence includes Data’s head! They travel to the planet they think the aliens are from and only Data in the end can see them. While he ends up being sent to 1893 and looks for the aliens, the Enterprise tries to figure out why the aliens might be going back to their history and if it’s a threat. Guinan plays a central role here, telling Picard in the present that he must go on the away mission while Data recognizes her in a newspaper and goes to meet her in 1893. Soon the away team is able to create a device to see the aliens and find that they are killing people in the 19th century. The team follows the aliens through a portal back to 1893 where they are eventually rejoined with Data and meet Guinan. After an encounter with the aliens, an explosion causes Data’s head to be removed from his body and Guinan is injured. Everyone accept Picard travels back to the present and the Captain sends a message to his team with the solution to their problem using Data’s head which they reattach in the present!
There are a lot of great things about this episode. It’s interesting to see Data consider his own demise and it’s nice to get a glimpse into Guinan’s past. Given her longevity, it’s fun to see what she’s been up to during this time and of course see her deal with knowing what’s happening in the present but unable to tell anyone for fear of changing things. Seeing Data’s head contain the solution was also a great idea to tie everything together, using the catalyst that started all this to end it.
“Endgame,” Voyager Season 7
The Voyager finale centered on time travel, starting with a 10 year anniversary gathering for Voyager’s return home which was a journey that took them a total of 23 years. Wanting to change things for the better, the older Admiral Janeway finds a way with some help to travel back in time to Voyager. The Admiral convinces them to go into Borg infested space because there’s a way to head home much faster. Thanks to future technology and tactics developed by Janeway, they’re able to resist the Borg and find a transwarp hub. Instead of heading straight home, the present Janeway wants to destroy the hub so the Borg can’t travel everywhere so easily, thus saving lives. The two Janeways argue and the future Janeway tells her present self everything she’ll lose if she doesn’t take the opportunity. Instead of doing just one or the other though, the two Janeways put their heads together and come up with a way to destroy the hub and use it to get back to the Alpha Quadrant.
While this episode doesn’t use time travel in the most unique way, it does seem like a fitting end for the series since it focuses on Janeway. It’s not hard to imagine that after all those years she’d still be trying to figure out a way to help her crew. It’s great to see the two Janeways work together and to learn about what would happen if the voyage home took so many years.
“Past Tense,” Deep Space Nine Season 3
In this Deep Space Nine two-part episode Sisko, Dax, and Bashir disappear during a beam down to Earth and arrive in 2024. Separated, Bashir and Sisko end up in the Sanctuary District days before a historical event known as the Bell Riots, which is going to spark important changes in society. When a fight breaks out and a man intervenes to help, he ends up getting stabbed to death and turning out to be Gabriel Bell, the man who was supposed to be a hero during the riots and give them his name. Sisko and Bashir decide they have to make sure the role Bell played in keeping hostages alive takes place, so they decide to do it. Meanwhile those on the Defiant realize the timeline has been changed and the Federation is gone. Sisko takes on the role of Bell and helps get the messages from the Sanctuary residents out to the world. Eventually the riots end and Sisko is shot, but doesn’t die and the hostages are alive. They slip Bell’s ID card onto one of the dead bodies so history can be saved and Sisko asks the guards to tell the truth about what happened before he and the others return to their own time.
This episode uses time travel to present a rather sad yet hopeful view of humanity. It shows the very worst of how we can treat others, but also how things can change for the better. It’s interesting to see how those from the future view the situation in 2024. The episode does use the common trope of one of the crew needing to take on the role of someone from history to save the timeline, but that doesn’t keep this from being a stellar episode.
“Year of Hell,” Voyager Season 4
This two-part episode of Voyager gives us a lesson in what can happen when you mess around with time too much. First we see the Krenim trying to erase a whole species, the Zahl, from time, which they succeed in doing. This causes a weak Krenim ship Voyager encounters to suddenly become a more powerful one as their timeline is changed. Now in this area of space, Voyager is in extreme danger and they start to lose people as the Krenim attack them. Meanwhile the Krenim continue to make changes to time and it’s only when Voyager makes modifications to their shields that they start to notice. Eventually we learn that Annorax is changing time so much in an attempt to save his family, who died thanks to changes he made in the timeline years ago. Unfortunately whatever he does, they’ve yet to be restored. Everyone except Janeway eventually leaves Voyager and in a confrontation with Annorax’s ship the timeline is reset.
While the reset button erases everything that happened over the course of these episodes, which some might not enjoy, it definitely does some fascinating things with the time travel concept beyond that final move. The whole story is a lesson in the problems that can result when you change too much in time. Plus even though the story gets erased, it put our crew into some excellent dire situations for an action-packed two-parter!
Star Trek DS9 The Visitor
“The Visitor,” Deep Space Nine Season 4
Here we see an older Jake explaining to a young aspiring writer why he eventually stopped writing. He explains that at 18 he went with his father on a trip to watch an inversion of the wormhole, but it caused a problem in engineering and Sisko disappeared. Jake explains what happened as the years past and things changed on the station. When Sisko reappears, they discover that he has been pulled into subspace and keeps going in and out of a place existing outside of time. Jake is happy for awhile in life, but that changes when his dad appears and disappears again. He dedicates his life to finding a way to help his father, but nothing works. While he tries to listen to his father and rebuild his life, he eventually comes to the conclusion that he is the one keeping his father in subspace and decides he has to die so that his father will return to the moment of the accident. Sisko is horrified, but it works.
This is a beautiful episode because of its focus on Sisko and Jake. The closer look it offers at their father and son relationship is very touching. Sisko being stuck in subspace provides a unique twist on the time travel idea as he’s stuck in one point but gets to periodically experience what’s happening over the years as we see time pact. Being flung back to the present with Jake’s death is a sad scene, but also a very moving solution as it shows how deep Jake’s love for his father goes.
“All Good Things…” The Next Generation Season 7
The finale for The Next Generation uses the idea of time travel in a clever way. Here it’s Picard’s mind that is jumping between different points in time. He is going from the present to the future where he is an old man to the past, which takes place during Enterprise’s first mission. Picard struggles to figure out what is going on and in both the past and the present the Enterprise discovers a strange anomaly. Eventually Q makes an appearance to explain how the trial we saw in the premiere has been continuing this whole time and now Picard must figure out what is going on with the anomalies in order to save humanity. It takes all three Enterprises coming together to stop it and we learn from Q that the Continuum wasn’t exactly convinced Picard could solve it. In the end the crew enjoys a poker game and discuss the future Picard saw, how they drifted apart, and how they can prevent it.
This episode is one of the most interesting uses of time travel in Star Trek. It’s not just a jump one-way or the other, but involves jumping into multiple times that Picard needs to figure out how to navigate since there are three different crews! It offers a very fitting conclusion for the series as it explores both the crew’s past and future before the mystery is solved and they are all able to come together in the present.
“Trials and Tribble-ations,” Deep Space Nine Season 5
This episode begins with a visit from the Department of Temporal Investigations to the station where they question Sisko about taking the Defiant back in time. While retrieving the Orb of Time on Cardassia, they pick up a passenger who turns out to be the Klingon spy Darvin from The Original Series. He uses the Orb to take them back to the time of the episode “The Trouble with Tribbles” and the K7 space station. Realizing what Darvin is up to, they split up into two teams in order to find and stop him. One team goes to the old Enterprise and the other to the space station. As the crew tries to stay out of the way and not change history, they discover Darvin has hidden a bomb in a tribble. They desperately search all the tribbles and eventually find the one that is the bomb with the poisoned grain. They return to their own time when Kira figures out how to use the Orb, but before they do Sisko makes sure to talk to Kirk!
This is an extremely fun episode. From Worf explaining his dislike of tribbles and why Klingons look different to Dr. Bashir wondering about a predestination paradox to the characters interacting with The Original Series crew, it does an amazing job of melding the two series for one of the best time travel episodes in the franchise.
“The City on the Edge of Forever,” The Original Series Season 1
McCoy accidentally injects himself with too much cordrazine and beams down to a planet where the Enterprise found a time disturbance. On the planet they discover the Guardian of Forever which is essentially a time portal. When McCoy just jumps through, it causes a change in the timeline and the Enterprise disappears. To set things right, Kirk and Spock follow McCoy to the 1930s where, after grabbing some appropriate clothes and using the Vulcan nerve pinch on a police officer, they realize they’ve arrived about a week before McCoy. They run into Edith Keeler who they decide to work for so Spock can buy parts to build a device to figure out what McCoy will change. Spock works hard to complete his project while Kirk and Keeler fall in love. It’s then that Spock tells Kirk Keeler is the point in time they have all been drawn to. McCoy somehow keeps her from being killed and so they have to let her die in order for their future to be restored. It presents a problem for Kirk who has feelings for her, but in the end he lets her death happen just as they’re all three reunited. Kirk stops McCoy from moving to save her and they return to the present where everything is back to normal.
This episode seems like a regular time travel episode at the start with them having to go to the past to restore the timeline, but the characters make it so much more. It’s a story that’s a lot of fun thanks to the great dynamic between Spock and Kirk and also very emotional due to Kirk’s struggle with accepting he has to let go of Keeler.
“Yesterday’s Enterprise,” The Next Generation Season 3
Topping my list is this Next Generation episode where the current Enterprise discovers a temporal rift and the Enterprise-C, lost 22 years ago, enters their present time. This journey from the past changes the current timeline so that the present Enterprise becomes a ship in the middle of a war with the Klingons and Tasha Yar is alive. Guinan is the only one that realizes things have changed and tells Picard the old ship has to go back to its own time. Unfortunately their ship is so badly damaged that sending them back to the Romulan attack in their time means certain death. Picard struggles with how he could ask them to do that, but ultimately trusts Guinan. As the old Enterprise prepares to go back, Yar realizes Guinan looks at her strangely and finds out that she’s supposed to be dead. Learning that her death was empty and without purpose, she asks Picard for permission to return with the past Enterprise so she can at least have a death that matters. Picard gives his permission, the ship goes back, and immediately the timeline restores itself.
This episode uses the time travel concept in a great way. Everyone is aware that the other ship came from the past, but the present Enterprise is none the wiser that their own time has changed other than Guinan who just has feelings about it. The old and present crews’ interactions are fascinating as we see how just one moment can change so much of the future and the courage it takes the Enterprise-C to be willing to make such a sacrifice. This episode also has amazing character interaction between our Enterprise crew. It shows us the deep trust that exists between Picard and Guinan as well as gives Yar a much better send off than she was given the first time around. Like “City on the Edge of Forever,” it’s the characters in this story that make it so much more than your usual time travel episode.
Tell us which Star Trek time travel episodes would top your list in the comments!