Changed My Jumper

"Oh, should've known, the way you guys are blending in with the local colour. I mean, Flag Girl was bad enough, but U-Boat Captain?"

- Captain Jack Harkness speaking in World War II London, Doctor Who, "The Empty Child"

When people are engaged in Time Travel, they will very frequently be wearing clothing that is inappropriate or out of fashion for the time period. After the obligatory initial comments about the time traveler being dressed "very strangely", the locals will all, in effect, shrug and move on, and however bizarre or inappropriate the clothing may be by their standards, they will rarely mention it again. An Improbable Hairstyle doesn't faze the peasants, either. Occasionally caused by Limited Wardrobe. Of course, in some cases, it's not a problem because Fashions Never Change.

Necessarily averted if you Can't Take Anything With You -- which just makes the time traveler stand out more.

(Note: For those of us Separated By a Common Language, a jumper is a sweater, not a dress for little girls. Or a kind of conductor. Or a guy on a bridge. Or a cable.)

Anime and Manga

 * Kagome from Inuyasha wears an extremely short skirt in feudal Japan. Near the beginning, a man comments that "Her kimono is shorter than mine" while fingering her skirt. After this, though, aside from a rare passing comment about "strange clothes", no one she meets is ever really surprised by her modern clothes and hair.
 * Considering how much school she misses because of San Dimas Time, one wonders exactly why she wouldn't bother with a more practical outfit whenever spending extended time in feudal Japan, aside from the obvious.
 * It's less that than it is an ingrained cultural habit. After elementary school, Japanese schoolchildren are conditioned to wear their school uniforms on school days, period, no exceptions--even after school. Sundays and holidays are no-uniform days, but most junior high and high school students are expected to remain in uniform until they go home for the night.
 * Given that Kagome is possibly the most powerful miko alive and she's traveling with a powerful half-demon at her side... yeah, the skirt is possibly the least unusual thing about her.
 * Hitomi in Vision of Escaflowne goes gallivanting through the fantasy world with knights, princesses and giant magical robots, wearing her school sailor uniform. She gets some comments about strange clothes in the early episodes, though. In their defense, they did try to get her into a more... appropriate dress, but then she had to run down Van and a big, billowy dress really gets in the way of a good runner.
 * Averted strongly in Tsubasa Reservoir Chronicle, where nearly every stop (longer than a day or so, anyway), involves the main characters acquiring clothing that would be appropriate in the local culture. More often then not, they are skipping dimensions, not time traveling, but the concept still applies, since the worlds they visit have a great diversity of historical settings, magical abilities, technology, urban vs rural, or even non-human inhabitants. Fai's fur coat would be out of place anywhere, so he seldom wears it. If they are wearing their own clothing, someone is likely to comment on how strange it appears. Basically, this gave CLAMP an excuse for endless costume changes.
 * CLAMP seems to love changing costumes every episode. They came up with an excuse in Cardcaptor Sakura, too.
 * Harukanaru Toki no Naka de - Hachiyou Shou (not quite a Time Travel, but close enough) averts the trope only partially. It's implied that Akane, Tenma and Shimon do look strange in their school uniforms to people in Kyou; however, the trio is given a chance to change into local clothing. The result is mixed: Akane in particular ends up trading her jacket for a short big-sleeved... thing... while the rest of her clothes, including short skirt, is left intact, and her short hair is also quite a contrast to the local standards, yet this hardly gets commented on.

Comics

 * On the rare time-travels of Milligan's Shade the Changing Man, it was easily Handwaved by Shade only appearing to personalities known to stay under the influence of substances, sometimes including hallucinogens. In one unique aversion, all of Hotel Shade and everything inside reverted gradually to earlier analogues and fashions, until they finally arrived in colonial Salem. Constantine mused on the fit of various underwear through history.
 * A comic special (Mandy?) featured a girl who sat in an a coach in a museum being transported back to the same coach in the Victorian Era. Once she explained that it was normal to wear mini skirts back home everyone accepted hers. Also pointing out that back home many secretaries were women was sufficient to get her the job.

Film
"Doc: What idiot dressed you in that outfit?
 * Inverted in Kate and Leopold. Leopold travels to the present and continues wearing his coat. He sees Kate and mentions that "women who wear pant are not to be trusted", but only jokingly.
 * Given that he's in New York, it's not unusual that people don't care how he dresses.
 * Averted in the first Back to The Future, with people remarking on Marty's hazmat suit and vest throughout the film. Back to The Future Part III also subverts this: Marty's cowboy outfit (assembled by 1950s Doc Brown, who assures Marty that it is, in fact, "authentic") is horrendously out-of-place in 1885 Hill Valley.
 * In the latter film, we get this memorable exchange after Marty meets up with Doc Brown in 1885:

Marty: You did."


 * Also averted (in another fashion) in the second film, where Doc gives Marty local clothing so he can disguise himself as his own son. However, he doesn't have to change out of his T-shirt or blue jeans (other than turning out the pockets, since in 2015 people wear their pants inside-out).
 * Totally avoided in the Terminator series. Nothing dead (unless it's surrounded by living tissue, like the terminators) can be sent through a time machine, so time travelers arrive naked and have to steal contemporary clothing.
 * Though the flashforwards also avoid this trope through the simple expedient of describing the future as a grim and endless theater of war, so that no matter what fashions might have appeared between, say, 1984 and 2004, the humans' clothes are all ripped to shreds, patched with whatever other fabrics and thread (and skill) were available, and covered with layers of dirt interspersed with sweat and cordite.
 * The Time Machine (2002). After the first time jump, the main character is given directions by a friendly woman on a bicycle. Both clearly think the others' mode of dress is unusual, but are too polite to say so.
 * Of course, thanks to the movie, this bicycle outfit inspired a Real Life version.
 * Averted in Somewhere in Time (1980), where the main character tries to buy accurate period costume for the time he is traveling to, but is informed by pretty much everyone he meets that his clothes are several years out of fashion, which makes him stand out significantly in the high society he is visiting.

Literature

 * Inverted in Magic Tree House and Kat the Time Traveler books, in which the characters usually find themselves in the typical clothes of the era. Occasionally Jack and Annie [in Magic Tree House] have kept the clothes they had originally (usually the most impractical clothes possible for the era, such as swimsuits in the Ice Age), but this is never commented on by any natives of the time they may meet.
 * Probably because in the MTH series, Morgan, their magical guide, likely warned the natives in advance. IIRC, the kids asked why the natives were helping, which the answer was along the lines of "A woman came in my dreams and told me to help you." She could have explained to the helpers, but that doesn't explain why nobody else wonders about them.
 * The Pendragon Adventure book series completely avoids this - probably two-thirds of an Acolyte's job is making sure that period and world-appropriate clothing is available to the main characters. Of course, in this case it's more dimensional travel than time-travel, but the spirit is the same (not to mention that two of the "Territories" are a past and future version of Earth, respectively).
 * In the Pratchett book Johnny and The Bomb, the kids decide to get disguises before going back to the WW 2-era version of their hometown again (the first trip being accidental). The skinhead Bigmac's idea to scrounge up a military uniform would have been better if it hadn't been a German uniform. Kristy was the picture of 1940s glamour...and, being 13, looked to 1941 eyes like a little girl playing dress-up. Johnny managed to scrounge up clothes that were reasonably authentic to what a kid his age might've had- and Kristy criticized him for it.
 * The Devils of Langenhagen, a short story by Australian sci-fi author Sean McMullen. The protagonist, a German pilot in an Me262 squadron in the last days of WW 2, realises there's something odd about the two pilots (and their wives) who've turned up with their unusually advanced aircraft (a Horten 229 and a Japanese Shinden canard fighter) because they're not dead-tired, starving and filthy like the rest of the squadron. They even have cigarettes! It turns out they're time travellers out for some thrill-seeking.
 * Foop!. The character's somewhat naive thoughts on how millenium-turn era citizens dress (obscene t-shirts) ends up not mattering because they had to go to Mardi Gras.
 * In Kir Bulychev's book A Hundred Years Ahead, a boy from 1976 ends up in 2082 - and simply tells the people he's dressed up for a masquerade ball.
 * The hero of L Sprague De Camp's Lest Darkness Fall is transported from Rome in 1938 to the same spot in 535 CE. He's wearing a light wool suit, necktie, modern shoes and hat. No one seems to particularly notice.
 * Discussed and averted in the Time Scout series. Even small changes in dress are considered dangerously anachronistic and treated as life or death.
 * The Time Machine Choose Your Own Adventure books may or may not pay attention to this. In Quest for King Arthur, for instance, when you time-travel to a modern-day museum, the tour guide will sarcastically comment on your Medieval costume. On the other hand, in The Mystery of Atlantis you're wearing nothing but a Greek chiton and yet can time-travel to locations such as nineteenth-century Great Britain or pre-Columbian Mesoamerica and nobody ever notices anything amiss!

Live Action TV
"Malokeh: The female seems more resistant to the cold than the male.
 * Doctor Who has had this a fair few times and it's sometimes remarked on by the locals. There are also some interesting subversions.
 * The title of this entry comes from "The Unquiet Dead", in which this trope is played straight by Rose and subverted by the Doctor. In that episode, the Doctor tells Rose to change her 21st century outfit into something more appropriate for the 1860s, otherwise "You'll start a riot, Barbarella!" The Doctor, however, merely changes his jumper and Charles Dickens duly comments that he looks like a "navvy".
 * The quote comes from "The Empty Child", where Rose is wearing jeans and a Union Jack T-shirt and the Doctor is in his usual leather jacket -- one worn by German U-Boat captains. In London. During the Blitz.
 * Amy Pond is the absolute champion of this trope. She's managed to wear a mini-skirt pretty much everywhere.

Amy: I dressed for RIO!"

"Colonel: What is that? Is that a uniform of some kind?
 * Another example is from the end of The Seeds of Doom, where due to a TARDIS error, Sarah Jane Smith ends up walking out into Antarctica -- in a swimsuit.
 * One aversion of the trope is from The Talons of Weng-Chiang, in which the Doctor puts on a Sherlock Holmes style outfit (complete with deerstalker) and Leela (her of the leotard) puts on a Victorian style dress.
 * In "Tooth and Claw", Rose Tyler dresses in a T-shirt and denim minidress for a visit to 1979, and ends up in 1879 instead. The locals assume her to be mentally ill and take to referring to her as "the wee naked child".
 * Possibly the most extreme example of someone noticing the incongruous clothes is in the Spin Off novel The Many Hands, where a soldier in 18th century Edinburgh comments on Martha's "pantaloons", and she sarcastically asks if it's against the law. It is.
 * In Ghost Light, Redvers Fenn-Cooper tells Ace that she's barely dressed, and later, Reverend Ernest Matthews is shocked at the Doctor "parading [his] shameless wantons", so the Doctor sends her off with Gwendoline to get something more suitable for Victorian England. It doesn't work the first time...
 * Lampshaded in the 2008 series, where Donna asks whether her clothing (jeans, tunic top) won't be a little conspicuous in a Roman city in AD 79. The Doctor's answer: "Nah, ancient Rome? It's like Soho. Anything goes." Sadly, it turns out the TARDIS landed in Pompeii instead. Later in the same episode, Donna, trying to fit in, is shown wearing a stola instead.
 * The Doctor himself, in the original run, compensated by dressing so outlandishly he was simply never in fashion: the fourth Doctor's scarf and bohemian coat, the Sixth's multicoloured coat, and so on.
 * Sarah Jane just happens to dress up in (2nd Doctor companion) Victoria's outfit before the events of Pyramids of Mars.
 * Lampshaded in "The Shakespeare Code", when the Doctor tells Martha to just walk about like she owns the place -- it works for him. She gets some looks and comments about being black, but is otherwise fine. However, a few episodes later in "Human Nature", this comes back to bite her hard when she's stuck in 1913 England and faces racial discrimination from everyone.
 * In The Sarah Jane Adventures story The Temptation of Sarah Jane Smith, teenage assistant from 2009 Rani Chandra time travels back to 1951. Everyone is shocked to see her in such ridiculous clothes and wonder if it can really be the fashion in "the Punjab".
 * She, hilariously, assumes at first all the strange looks she's getting are due to her race, when she's really getting the looks due to her clothes, and probably only getting away with it because she looks foreign.
 * In the same episode, knowing that she's going back in time, Sarah Jane dresses appropriately for the time period. Apparently "the 50s came back in the 70s". Luke is suitably embarassed.
 * Repeatedly in Star Trek the Original Series:
 * "Tomorrow is Yesterday": Captain Kirk beams down to a 1960s U.S. Air Force base while wearing his Star Fleet uniform.

Kirk: This little thing? Something I slipped on."

"Kirk: We seem to be costumed a little out of step with the time."
 * "City on the Edge of Forever": Kirk and Spock are in 1920s New York wearing their Star Fleet uniforms.


 * Averted in "Assignment Earth": When Kirk and Spock beam down to the 1960s United States, they wear appropriate clothing.
 * "All Our Yesterdays": Kirk, Spock and McCoy accidentally end up in the past of an alien planet while wearing their Star Fleet uniforms.
 * Star Trek IV the Voyage Home, the crew goes to the then-present, 1986, and none of their clothes seem excessively out-of-place.
 * Except maybe Spock's head-to-toe white robe and headband. Of course, they are in San Francisco.
 * This is justified, actually. Before filming Paramount had non-Trek actors walk around San Francisco in costumes. Nobody noticed.
 * Well, with the rank insignia and more obvious military trappings removed, the late 23rd century Starfleet uniforms really aren't all that abnormal-looking...and remember, only Kirk and Uhura were even in uniform. Everyone else was wearing the same civilian clothing they wore when they stole the Enterprise in the previous film, and their civvies are pretty much identical to late 20th century attire.
 * Humorously averted on Star Trek Voyager: when the crew of Voyager find themselves in Los Angeles in 1996, they dress up to blend in. But one look at of the odd outfits on the boardwalk and gang-banger Tuvok comments that they could've worn their Star Fleet uniforms and probably no one would've noticed.
 * Parodied in "Almost...But Not Quite" by Dayton Ward (Star Trek: Strange New Worlds II) where two Temporal Investigations agents (based on a report of Kirk's visit to 20th Century San Francisco) disguise themselves as punk rockers...when visiting Griffith Observatory. Needless to say, they stick out a bit.
 * Also, on one episode of Deep Space Nine, several characters found themselves in the Original Series, and changed their jumpers to fit the Star Fleet uniform of the period.
 * It formed something of a running gag in The Next Generation. Whether on the Holodeck or traveling into the past, people would assume that the characters' uniforms were pajamas (Or in one case, a bellhop's uniform). Can't really blame them.
 * Avoided by Spock in the Star Trek the Animated Series episode, "Yesteryear"---in which he asks for Vulcan items to use to play his own cousin to save his own life.
 * Averted in Star Trek Enterprise. When Captain Archer wakes up in an Alternate History version of WW 2, it's assumed from his jumpsuit with 'Enterprise' symbol that he's a survivor from the sunken aircraft carrier of the same name.
 * Another running gag in Time's Arrow; according to locals, the android Data is actually French, and he was kicked out by his girlfriend in the middle of the night. At least Mark Twain doesn't fall for it... Jack London does, though.
 * Averted in "Accession" where a time-displaced Bajoran emerges from the wormhole and his 22nd Century clothing looks exactly the same as that of the 24th Century.
 * The Time Tunnel: modern day clothing, various time periods
 * One of the leads actively averted it in the first episode, but never got that chance afterwards.
 * Its About Time: astronauts wearing space suits in the prehistoric past
 * Averted in the Lost In Space episode "Visit to a Hostile Planet", where the Jupiter II goes back in time to the 1947 United States and the Robinsons walk around in their shiny silver space suits. Because of their dress, the locals think that the Robinsons are space aliens.
 * Played with in Lost in Austen, where Mr Darcy and Miss Price are able to wander around modern London in outfits from the early 19th century without anyone commenting. Whether this is because nobody thinks it's that weird in a city that diverse, or the British are just too polite and reserved to comment, is uncertain. On the other hand, when Miss Price first arrives in Pride and Prejudice land she has to excuse her leather jacket and jeans as otter-hunting clothes. The degree of cleavage she's showing causes Mr Bingley some discomfort, as well.
 * From the cleavage-revealing clothes often used in historical dramas, that shouldn't have been a problem. Or is that just a Fan Service version of history?
 * Generally the cleavage-exposing dresses were considered acceptable as evening wear but not during the day.
 * In an episode of Farscape, Moya's crew find themselves on Earth, on Halloween, in 1986. Aeryn's faux-hippie outfit is... interesting, to say the least.
 * In Stargate SG 1 "1969" the team are sent back to the titular year and swap their uniforms for stereotypical hippie garb. This is, however, justified - they're on the run and want disguises that'll make people dismiss them.
 * On Voyagers, the costume of the travelers almost always got attention -- particularly Phineas' chest-baring pirate shirt. In most episodes they'd quickly find local garb. In more than one, a local lady would mourn the passing of the shirt.

Real Life

 * This trope is the entire point of Pretend To Be A Time Traveller Day, started by the webcomic Dresden Codak. (See below.)
 * During filming for Star Trek IV the Voyage Home the director was somewhat disappointed that the locals didn't even blink at the actors wandering around in strange uniforms. It's San Francisco, you have to work a lot harder than that to get double-takes.
 * It wasn't even during filming, it was prior to filming, and it was non-actors in the full Starfleet "Red Jacket" uniforms.
 * Of course they weren't strange uniforms. They were probably recognized as being Star Trek uniforms and then not given a second glance.

Tabletop Games

 * In the time-travelling RPG Continuum, spanners are cautioned to be careful of this once they learn to travel more than a few years in a single span. One of the flavor-text stories in the sourcebook has a mentor living in the early sixties call out one of her charges for wearing a peace sign, even though it's only a few years before it would become popular.

Video Games

 * Skillfully averted in The Journeyman Project series. In the first game, the character, in a form fitting biosuit, is expressly forbidden from coming into contact with any intellegent being originating from the time he is traveling to. In the second game, the new Jumpsuit technology, features a cloaking device that can conceal the character by bending light around him. In the last game, talking to the locals is necessary, so the new suit can copy the external appearance of any individual of the time period, including attire, facial features, etc. It even allows for the generation of a fake cane and removable top hat in the game's ending.
 * Agent 5 gets seen several times by medieval knights in the second game. Fortunately, his metallic suit is mistaken for armour, and most of the witnesses die immediatelly afterward. Attempting to wear the suit into the public in BC Mayan times results in him being immediatelly assumed to be a god, resulting in Have a Nice Death by screwing up history.
 * Chrono Trigger. While soldiers in 600 AD do comment on Crono's clothing, Lucca somehow manages to get past them later on, and no one notices the other party members wandering around in strange clothes (not even the cavewoman running around in a fur bikini). Even Crono's mom, who can talk to other party members says "young ladies shouldn't dress like that".
 * Degrees of lampshades are hung on the subject. The Cavemen will make weird comments on your shiny stones and such, however a medieval guard has no problem talking to a robot from 2000 some odd years into the future.
 * Star Ocean: Needed for the human to enter the first town
 * And then totally ignored for the subsequent games, which while not involving time travel, are functionally equivalent in having space travelers visiting primitive planets.
 * The Orion Agenda, an IF Comp text-adventure, requires players to adopt the appearance of the natives. You also need to use the Universal Translator in order to avoid being detected as well.
 * In Kingdom Hearts, the trope is averted in some worlds such as Halloween Town, Timeless River and Space Paranoids where the main characters change their clothes to fit the world they're in. In Atlantica and the Pride Lands they even change their bodies into animal bodies. On the other worlds they don't change their clothes, but nobody seems to take notice. It might not count as time travel, but most worlds are set in different time periods.

Webcomics
""Yep, I think they're time travellers."
 * Subverted in Dresden Codak, where the time travelers try to blend in, but fail, and are identified as time travelers on sight by Alina, who compares them to historical reenactors:

"You think so?"

"If the future did a documentary of the last fifty years, this is how badly the reenactors would dress.""


 * Scary Go Round, while avoiding this trope, gave a good demonstration of why it can be necessary to move a story along. Amy: "If one more person shouts 'Whore' at me, I'm going to kill them."

Western Animation
"Danny: Oh, great, I blend in."
 * Averted in Futurama: Prof. Farnsworth enters a 1940s diner (due to time travel) wearing a zoot suit, and Leela enters wearing a poodle skirt, sweater and sunglasses.
 * Although by the year 3000, Fry's red jacket and blue jeans combo is deemed snicker-worthy.
 * Team Possible found themselves wrongly dressed when they entered the Bad Future in A Sitch in Time because, according to little more than mere fashion rules, everyone should be wearing Shego's uniform.
 * Subverted in a Danny Phantom episode where Danny's time travel to the 1980's reveals that his black jumpsuit is actually fitting for that time period.


 * In the Men in Black cartoon, Agents Jay and Kay are sent back in time to a Wild West town. Agent Kay's suit transforms into period-appropriate clothing. However, Jay is stuck with his normal suit and is mistaken for an undertaker.