"Many such journeys are possible. Let me be your guide."
"Walk through this portal, and you will end up in Nazi Germany."
— Thor, Kung Fury
Who needs a Steampunk Time Machine or alien police boxes? Certainly not someone with a portal to the past. It might be the result of eddies in the time stream or a magic spell, or it might remain unexplained in a Magic Realism style. However it happened, the portal is your two-way ticket to time travelling fun.
The portal is usually synched up with the modern day, so that an hour on this side is equivalent to an hour on that side, thus allowing relationships to develop and justifying the existence of San Dimas Time. However, if the story is a little more tragic then time might move faster on one side, making the character on that side age much faster.
If a melancholy ending or moment of tension is required, a Portal Slam may come into play.
See also Meanwhile, in the Future…, San Dimas Time, Portal Door, Our Time Travel Is Different.
Note: Please don't duplicate entries between this trope, Meanwhile, in the Future…, and San Dimas Time. This trope refers to a specific form of time travel, "Meanwhile, in the Future..." refers to when a story follows different plotlines across different time periods, and "San Dimas Time" is when the narrative of a time travel plot combines with Race Against the Clock.
Examples
open/close all folders
Anime & Manga
- Inuyasha: The Bone Eaters' Well connects the two time periods in sync, so that time flows at the same rate on both sides.
- In Shinobi Life the portal is in a lake in Kagetora's time, and connects to one above a skyscraper in the modern day. We later learn that there is another portal from the modern day to the future, which Beni's mother often used.
- In Thermae Romae there is a portal between a modern day bathhouse in Japan and a spa in Ancient Rome.
Films — Live-Action
- The Time Viewer in Déjà Vu (2006) is permanently set to look at the past about 5 days earlier, and this interval cannot be changed, because they've just accidentally stumbled upon the 'future end' of the type of wormhole described under Real Life below. Oddly, no one thinks of looking through the 'past end' to see the future.
- In Frequency, apparently because of the Aurora Borealis, a ham radio set sends and receives signals between the present and thirty years ago.
- Both 2000 Korean film Il Mare and its 2006 American remake The Lake House revolve around the same central premise, namely a magical mailbox that transfers letters and packages back and forth precisely two years through time, from a man in 1997-1998 to a woman in 1999-2000.
- Indiana Jones and the Dial of Destiny: Time travel is possible through random "time fissures", which are in effect naturally-occurring wormholes through spacetime. Finding these fissures requires incredibly complex mathematics.
- James Rolfe's film Legend of the Blue Hole speculates that the titular Blue Hole, a mysterious pond in the New Jersey pine barrens where people frequently vanish, is actually a time portal, and diving into it will cause you to resurface in the past. Jason and Samantha jump into the pond in 2003 and resurface in 1971, though Jason later draws a diagram showing that believes diving deeper into the Blue Hole would take you ever further back.
- In the 1999 film The Love Letter, a modern-day American man finds letters written in the 1860s hidden in his antique desk. He fancifully responds to these letters by routing his own through a pre-Civil War post office, where they are mysteriously transported back in time to be delivered to the original writer (a previous owner of the desk), who then replies by hiding 'new' letters.
- In Mighty Morphin Power Rangers: Once & Always, Robo-Rita, the evil essence of Rita Repulsa in Alpha-8's body, kidnaps various Rangers, including parts of the original Mighty Morphin' team, to power a device to open a portal back in time to 1993, when the Evil Space Aliens' dumpster is accidentally unsealed. Robo-Rita plans to enter the portal to kill the original Mighty Morphin' team before they're ever formed, allowing her original self to conquer Earth unopposed.
- The Smurfs:
- The Smurfs has a portal that opens within a waterfall in the Smurf forest that transports whoever enters it through time and space... in the movie's case, into modern-day New York City.
- Gargamel opens up one near the Eiffel Tower in Paris in The Smurfs 2 in order to kidnap Smurfette, but since it's too small for him to go through, he sends Vexy through the portal to get her.
Literature
- Some of the cupboard portals in 100 Cupboards seem to work this way (others lead to other worlds entirely). Henrietta is very nearly killed when crawling through a random door drops her into the Battle of Actium.
- In 11/22/63, there is a stable portal in the back of a diner which leads to 1958. Interestingly, while time goes forward in the present, the other end always goes to the same second in 1958, effectively resetting on subsequent visits.
- The time doors in Chrono Hustle can travel to multiple different times and places, but the time syncs up between all of them, so a day passing in one time equals a day passing in another.
- The Brotherhood of the Conch: In The Mirror of Fire and Dreaming, the titular Magic Mirror serves as a portal from the present day to the Moghul Era.
- In the short story "Dandelion Girl
", a person claiming to be a time traveler explains that time machines default to this mode, with their destination time advancing at the same rate as their source time unless you deliberately choose to keep resetting the destination back. Whether that person is telling the truth, however, is a rather important question...
- The smuggler's cave by the beach in Rex Stone's Dinosaur Cove series. Tom and Jamie use it during low tide to go back to prehistoric times by walking forward on the dinosaur tracks within, able to return by walking on the tracks backwards as long as the tide is still low, and their Wannanosaurus friend is usually not far from the other side.
- Lynne Reid Banks' The Indian in the Cupboard series has the magic of time travel function this way, with Omri's dad speculating that time is spiral in shape, and you can "drop through a certain number of layers" to get to a point in the past, but if you then take The Slow Path (and live long enough) you eventually arrive back where you started. When someone is time-traveling using the magic, their present-day self is unconscious, so they have to be safely hidden and get back in time for nothing to go wrong (one side character is thought to have died as a toy-sized figure in what was, to her, the future because the people in her own time buried her seemingly dead body, and Omri's mother gets a nasty scare when she finds her husband and sons in the car looking like they somehow suffered carbon monoxide poisoning).
- In Stephen King's story The Langoliers, a "rip in time" causes all the passengers not asleep to disappear from a jet, while the plane and the sleeping passengers are sent back "a couple of minutes." The survivors must find out how to get back, and do so asleep, otherwise they too will disappear. They wind up a couple of minutes in the future but are able to sync up with normal time when it arrives.
- In Mary Poppins Comes Back, after Jane accidentally cracks an antique Royal Doulton bowl, the boys in its design come to life, and invite Jane to see their home. After she enters the design, she winds up 60 years in the past. When the boys and their great-grandfather attempt to make Jane live with them forever, Mary Poppins intervenes, and rushes Jane back to her own time.
- Miss Peregrine's Home for Peculiar Children has a cave near the town in which the main story takes place.
- The book The Daughter of the Regiment had a tiny time portal through which a boy watched a girl in the past grow up.
- The Cool Gates of the Morgaine Cycle can do this as a side effect of their Portal Network function. Unfortunately, anyone who uses them to create a Time Paradox triggers a civilization destroying Time Crash, which is why Morgaine is on her quest to destroy all the gates.
- The Nightside books have Timeslips, leading to both the past and possible futures, depending which one you stumble into.
- Stone circles work this way in the Outlander book series — but travel is really only ever something like "safe" if you have a certain assortment of precious stones with you, and it's got a very high fatality rate. (And as the heroine muses, the separation in the various times is roughly 200 years... just like in the folktales.)
- Julian May's Saga of the Exiles has a portal to six million BC, initially only one-way.
- First, Second, and Third Earth (past, present and future) in The Pendragon Adventure are linked by the Portal Network, and employ San Dimas Time.
- The Great Door of Time in Septimus Heap.
- Michael Crichton's Timeline has a wormhole that was accidentally discovered during a teleportation experiment. The wormholes leads to the past, specifically, to France in 1357note . The events in the present and the past are synced, although it's also implied that You Already Changed the Past (i.e. no changes in the timeline are possible). When the quantum mirror is damaged by a grenade, the lead technician fears the connection may be lost for good, as they have no idea how the link works.
- The Time Scout series by Robert Asprin is based around an ever growing network of periodically opening portals, each of which is tied to a particular spot and reaches back a fixed length of time (which varies from portal to portal).
- Murray Leinster's Time Tunnel is based on a "found" example, between 1964 and 1804.
- Lester del Rey's Tunnel Through Time involves the creation of a "time ring" that acts as a portal to the past.
Live-Action TV
- Dark (2017) The titular door in the cave with Latin inscriptions leads to a fork in the tunnel, where one may travel either 66 or 33 years into the past (at least from 2019). This door exists in 2019, 1986, and 1953, the other two being accessible from each via the door. The way the three "time zones" are portrayed is reminiscent of San Dimas Time.
- Doctor Who:
- In "The Girl in the Fireplace", the Doctor, Rose and Mickey come across a 51st century spaceship full of portals to the 18th century, including the titular fireplace. There's an element of Narnia Time as well, because the portals tended to jump ahead inconsistently.
- "The Doctor, the Widow and the Wardrobe": As part of his Christmas present for the Arwells, the Doctor hides a time portal to a 54th century forest inside a large wrapped box. It ends up getting used earlier than planned.
- The comedy Goodnight Sweetheart had the main character walking down an old cobbled street that would take him — and only him — back in time, where he fell in love with a World War II barmaid and committed time-travelling bigamy. Turns out it was due to the "harmonics" of time, and other characters could time travel but none of the main characters.
- Kamen Rider Kiva: a door within Castle Dran can send someone into the past, but many of the details are left vague. What's shown is that the door sends one back 22 years, and they remain there until they achieve the goal they sought to accomplish in the first place. In other words, time travel as the plot requires.
- Mirror, Mirror (1995) is built upon this trope, resolving around a magical mirror that can send people back and forth between 1919 and 1995. There are a few conditions; the mirror only works as long as it is in the exact same position in both eras, and it doesn't work for people/objects that already exist in the time period they try to travel to.
- Primeval: The show's central premise is that "time anomalies", depicted as freestanding glowing oblongs surrounded by floating shards, begin to open and permit the movement of creatures between time periods, resulting in a rash of prehistoric animal attacks in England spiced with the occasional far-future creature.
- Quantum Leap works like this from Al's point of view — the door that takes him to Sam is synced up so that if Al goes away to do something for five minutes, Sam will have to wait out those five minutes before he returns. One episode has changes that take place instantaneously from Sam and Al's viewpoint. Specifically, the episode has Sam and Al switch places due to a lightning strike. Mistaking this for a radiation spike, the Quantum Leap computer blocks the door to the holo-room. So Al has to send a letter to their future colleagues with a request to deliver at a specific point in time. As soon as he drops the letter into the mailbox, the door opens. Interestingly, this synchronization only applies after Sam arrives, replacing someone. The leaps themselves are instantaneous from Sam's (and the audience's) point of view, but appears to take a random amount of time in the future, often several days.
- The Red Dwarf episode "Stasis Leak" revolves around one of these. Lister wants to use it to save Kochanski; Rimmer wants to use it to save himself.
- In Siempre bruja, there is a time portal that is activated with a magic stone.
- The Korean police drama Signal involves the use of a magic walkie-talkie. Police detective Park Hae-young, in 2015, comes into the possession of the old walkie-talkie belonging to long-disappeared homicide cop Lee Jae-han. Hae-young finds that with the walkie-talkie he can talk to Jae-han decades into the past. Jae-han's transmissions lead Hae-young to discover a skeleton that Jae-han first found in the year 2000, while Hae-young in 2015 helps Jae-han with a serial killer case in 1989.
- Star Trek:
- Star Trek: The Original Series has the Guardian of Forever in the episode "The City on the Edge of Forever" (pictured). Kirk apparently assumes that the Guardian works on San Dimas Time (leaving orders for the rest of the landing party to go back through the portal when Scotty decides he's waited long enough), but it turns out not to (when he returns, Scotty says that he'd only "left a moment ago").
- On Star Trek: Discovery, the Guardian (masquerading as a human named Carl) opens a door for Philippa Georgiou that not only leads over 900 years into the past, but also to the Mirror Universe, where she appears in her Terran Emperor regalia. It may not have been the same Mirror Universe, though, as Georgiou was able to affect changes in it and then returned after dying. From Burnham's perspective, it took only a moment. But Georgiou's bioscanner recorded three months' worth of data in that moment.
- The Star Trek: Voyager episode "Eye of the Needle" has Harry Kim discover a wormhole that leads back to the Alpha Quadrant. The only trouble is, not only does it come out in Romulan territory, but Romulan territory twenty years earlier. May be Truth in Television: see Real Life below.
- The Star Trek: Deep Space Nine episode "Time's Orphan" has O'Brien's daughter Molly fall through one. They manage to pull her back, but their instruments are a bit off, and they pull her out ten years after she had gone through. Later, they let the now-feral Molly return "home" through the portal (which she's known for even longer than she'd known her family in her childhood), only to come across her 8-year-old self having just come through the portal the first time, allowing her to rescue herself in her own past. Or at least one version of herself.
- One is featured in the Star Trek: Strange New Worlds crossover episode "Those Old Scientists" where Ensigns Brad Boimler and Beckett Mariner from Star Trek: Lower Decks - set 120 years in the future of Strange New Worlds - use it to travel back in time (Boimler being sucked through by accident, then Mariner a little while later in a failed rescue attempt). The episode features the cast of Strange New Worlds trying to figure out a way to get both ensigns back to their home time.
- Star Trek: The Original Series has the Guardian of Forever in the episode "The City on the Edge of Forever" (pictured). Kirk apparently assumes that the Guardian works on San Dimas Time (leaving orders for the rest of the landing party to go back through the portal when Scotty decides he's waited long enough), but it turns out not to (when he returns, Scotty says that he'd only "left a moment ago").
- Part of the premise of Terra Nova; a "time rip" has been discovered that leads to an Alternate Universe (maybe) of the Late Cretaceous, some 85 million years in the past. The eponymous Terra Nova is an attempt to colonize the past, since the Earth That Used to Be Better of the 22nd century isn't a hospitable place to live anymore. Notably, the portal is only stable in space and time because of technology; the first person travel to the past before it was stabilized had to survive alone for 118 days before his backup appeared, even though they went through right behind him. It's also one-way for goods and people, and only two-way for communications. Everyone who travels through is committed to staying. The villains' plot is to convert the portal to two-way travel so they can exploit the past for resources and riches.
- The Time Tunnel is a secret government project that creates a Time Machine in the shape of a tunnel. Two Americans venture into it, and are transported into the past, and later the future. While the two men can sometimes communicate with Mission Control, and move around in the time steam, it's getting back home that's the tricky part.
- TRAX, the time machine of Time Trax, can only send its subjects approximately 200 years into the past. The show is inconsistent with its time travel. Some episodes claim that it's not actually time travel. They're just traveling to a parallel dimension that is 200 years behind. Thus, any changes to this timeline will not affect "their" present. Other episodes have the protagonist communicate with the future by placing ads in newspapers, something that wouldn't make sense if this was a parallel world.
Tabletop Games
- The game Feng Shui takes place in four eras (AD 69, 1850, 1996 and 2056) as well as the timeless realm outside of time, the Netherworld. These four eras are connected by various portals, and are synchronized to each other.
- In the Pathfinder adventure path Return of the Runelords, Runelord Alaznist uses an artifact to change history to aid her rise to power in the present day. To Set Right What Once Went Wrong the PCs must travel to the Dimension of Time, where they encounter the portals she left behind. They must use these portals to travel back themselves and undo Alaznist's meddling in order to negate the apocalyptic events spawned as a result.
Video Games
- Chrono Trigger has a whole bunch of these portals going to multiple "locations" in time, and always in sync. This doesn't explain, however, why the Epoch is also on San Dimas Time.
- In City of Heroes, the Midnight Squad uses one to access the ancient Roman town of Cimerora. There is also a portal that allows players to visit the original versions of revamped zones, but no missions take place there.
- The hub world of Crash Bandicoot 3: Warped is Dr. N. Tropy's Time Twister Machine, and each level takes place during an era of history (or, in some cases, the future) that's accessed via a portal through its use.
- Portals to both past and future figure prominently in Dark Fall 2 Lights Out.
- Fallout 2 has a special encounter that's a Shout-Out to the original Star Trek, in which you find a time portal called the Guardian of Forever (both named and visually designed after the one from Star Trek) that takes you back to just before Fallout, causing you to break the Water Chip and thus cause the events of the series.
- The Final Fantasy XI expansion Wings of the Goddess introduced Cavernous Maws, intimidating-looking examples of this trope that connect present Vana'diel with the Crystal War era.
- Kingdom Hearts II: The Timeless River is accessed this way. Pete's fervent desire to return to the days when things were better summons a door that connects to the past. When his actions there start threatening the present, Merlin conjures a second door so Sora, Donald, and Goofy can stop him.
- The Legend of Zelda:
- The Legend of Zelda: Twilight Princess has precisely one of these in the game. The door to the Temple of Time sends you to the interior of the temple as it was in the past. The entry hall is even replicated nearly exactly from the version in The Legend of Zelda: Ocarina of Time, including the same background music.
- The two Gates of Time in The Legend of Zelda: Skyward Sword: one in the Temple of Time (appropriately), the other in the Sealed Temple.
- Until it gets upgraded, the Harp of Ages in The Legend of Zelda Oracle of Ages can only activate dormant time portals in fixed locations. Once upgraded though, Link no longer needs to find a portal to travel through time but can do it anywhere except in the graveyard or near the black tower.
- Mario & Luigi: Partners in Time had time portals popping up all over the place, leading to different areas in the same time period.
- Ōkami: Hidden in the forest of Yoshpet is a gate that connects to Kamiki Village of 100 years ago, causing the protagonist to have to reenact a famous battle — in which the protagonist died.
- One of the main mechanics of Onimusha 3: Demon Siege is Time Dungeons. Locations where the 2 main characters explore simultaneously with 1 in the modern day and the other in the Feudal Japan era. The game's Exposition Fairy is able to use mirrors contained in those dungeons to traverse the 2 time zones, bringing essential information and tools with her. Though it does not seem that time continues to flow in her absence, at least while in those dungeons. Outside of those dungeons however time does indeed flow allowing the character she is not with to move through the world and arrive at the same location.
- Portal 2:
- There are a few user-made maps that use Hammer's world portal function like this. Most of them are just proof of concept levels, though.
- This fan puzzle features one. Apparently the portal gun can transport you across time as well as space.
- Portal Reloaded: Can use a Teleport Gun to be Thinking Up Portals that are this style.
- In Ratchet & Clank Future: A Crack in Time, this is how Time Travel is achieved for gameplay levels, allowing one to take or change things in the past to influence the present. This works different from the time travel used with the lever in the Orvus Chamber, which is more like rewinding a VCR. According to Word of God, the portals can only be created in existing temporal anomalies, explaining why the characters can't just make a Portal anywhere for their own ends.
- The MMO The Secret World has "Time Tombs" as part of the Egyptian Storyline. That being said, you can only take what you're wearing or carrying with you back and forth in time, and the Tomb itself only allows to go back as far as when it was first created. Any changes you happened to make are also subject to the laws of equivalent exchange, thus, if you planned to steal some sort of ancient artifact, it would have to be replaced by something of equal weight (usually a convincing forgery), and then hidden somewhere that hopefully no one else in history would find it. It is also notable that the Time Tomb only creates a "bubble" of area that can travelled back to, thus you're limited to affecting the timeline within roughly a half-kilometer of it.
- The Star Ocean series has a planet specifically dedicated to a portal to the past: planet Styx. It's used about thirty minutes into Star Ocean: First Departure, mentioned in The Second Story, and used in Till the End of Time to contact the 4th-dimensional beings that observe our MMO universe. That's right! We're all game characters that got pissed and came out of the computer to tell our creators to knock it off.
- A feature in one of the boss fights in the Dread Palace operation in Star Wars: The Old Republic. Players must enter both portals to the past and future to ensure that the boss is defeated in the present.
- Where in Time is Carmen Sandiego? (1997) has the Chronoskimmer, a handheld time machine that works by creating "Time Tunnels", which are essentially portals left behind as a result of its use. Da Chief admits that it was a design flaw they never got around to fixing- and a good thing they didn't, since the game has the player chasing Carmen and her thieves through time after they steal it.
- The Caverns of Time in World of Warcraft are all about this. It would of course be difficult, incredibly confusing, and quite pointless to do it in any other fashion.
Visual Novels
- The protagonist of Time Hollow has the ability to open these using his "Hollow Pen". He's not the only one, and any changes made by one Pen user cause "flashbacks" in others, giving them new places and times to open holes. Indeed, the Big Bad changing things shortly after Ethan gets his Pen is what starts the whole plot. And it turns out that anyone who steps through them will be removed from the flow of time, stopping them from aging from then on.
Webcomics
- Earth, 2068: When the STORMaDO portal is open, time passes at the same speed on both ends, and wireless communication through it is possible.
- This appears to happen briefly within the first couple strips of Girl Genius. The story hasn't caught up the wherever the future end was, though, so we can't be sure.
- Sydney Scoville has caused a problem in Grrl Power by travelling back from a deployment through some sort of dimensional portal. She thinks she has been gone for a few days at most; her return point is 57 days into the future. This isn’t actually a plot point, as such, and isn’t a time travel story but it DOES cause a wrangle over what pay she is due.
- The eponymous energy sphere in Recursion is a portal to the past. It also moves you through space as well as time: one end is on Celeria, while the other is in the distant past of Kass.
- Conversed in Tales from the Pit, causing another lost day of R&D productivity as the Pit enters a heated discussion about the best way to make money if you had a Time Machine that can only go back exactly 24 hours.
Western Animation
- Jackie Chan Adventures had this happened three times all involving the character of Jade. In each instant one could only travel in one direction through time, meaning they had to provide their own "return ticket."
- Kim Possible:
- The Tempus Simia allowed time travel to the past and to the future via portals it made when activated.
- The wristwatch time machines also created portals.
- The Owl House has Time Pools, randomly-appearing puddles of liquid which can transport someone to another time period. Luz and Lilith use one to go back to the 1600s and meet Philip Wittebane aka young Emperor Belos.
- A veritable part of the landscape in Samurai Jack: almost every episode features a new time portal that's invariably destroyed in the end to spite our poor samurai hero.
- The Superfriends episode "The Time Trap" uses this trope.
Real Life
- Physicist Kip Thorne discovered, using general relativity, a possible way to use wormholes to create links between time periods. The time-synching phenomenon is explained by the fact that after the wormhole/time portal is set up, both sides will be essentially at rest with one another, meaning that time must flow at the same rate on both sides.
- In 1911, academics Charlotte Anne Moberly and Eleanor Jourdain published an account of how, in 1901 during a trip to the Palace to Versailles, they found a road which led into the 1700s, where they saw historical figures including Marie Antoinette. Although most believe that the "Ghosts of Versailles" incident either sprung from the women misidentifying other guests in period dress or was a hoax plain and simple, the story remains a classic staple of real-life time travel urban legends (and was used in the French Historical Detective Fiction series Nicholas Le Floch, as well as referenced in the season 5 premiere of Warehouse 13).
