Multicultural Alien Planet

"Warden: Tell me about the qunari. Sten: No. Warden: Well, that wasn't what I expected to hear. Sten: Get used to disappointment. People are not simple. They cannot be defined for easy reference in the manner of: "The elves are a lithe, pointy-eared people who excel at poverty.""

- Dragon Age

A common decision that creators have when worldbuilding is if each planet is going to have a culture that spans the entire world, or if they have distinct ethnicities, cultures, and traditions.

This is the latter. Either the writer is attempting to subvert or soften the traditional Planet of Hats methodology, or they enjoy World Building itself. Planets are unlikely to be as heterogeneous as modern humanity -- most writers have trouble working that with humanity itself -- but there will be more than one defining characteristic for each race. The goal is to make each race as interesting and deep as a three-dimensional character, instead of a flat template to apply to any character from that race.

This trope is most notable for its appearance in Science Fiction; however, it also appears in other Speculative Fiction. In a science fiction work with only humans, this trope applies when multiple cultures appear in any given area, such as a Space Station or a planet. In a Fantasy story with fantastic races, this trope applies when there are different ethnicities or cultures within the races, such as more than one type of elf or more than one type of goblin. A given work may mix and match the tropes, giving Planet of Hats treatment to the villainous races, and Multicultural Alien Planet treatment to the heroic races. If a work has the same alien race on five planets, and each planet has a different ethnicity, then the creator is using both.

Examples of this trope are species with a tendency to possess diverse and varied cultures. There may be cultural or societal divisions, and ambitious writers might even suggest different languages among members of the same species. However, given the tendency to skip alien languages altogether, some will simply invoke Aliens of London and settle for giving alien species different accents or speech patterns. (Note: If the diversity is only in accents, the example belongs on Aliens of London, not here.)

Comics

 * Because Flash Gordon is set entirely on Mongo and doesn't do any standard planet hopping (at least, not until the strip's later years), Mongo is an incredibly diverse planet.

Film

 * In the Star Wars prequel trilogy, Naboo has at least two cultures, the Gungans and the humans.

Literature

 * In Out of the Silent Planet, the inhabitants of Malacandra come in three different species (not counting the energy beings), each with its own language. Furthermore, the sorns (giant feathered humanoids) come in at least two varieties - white (in the mountains) and red (in the deserts), and the hrossa (otter-people) come in at least three races -- black, silver, and crested. There might be more, but the viewpoint character wasn't on the planet long enough to tell, as he was vividly aware.
 * In the original Foundation novels, Trantor is barely mentioned beyond being a City Planet (and then eventually a Farm Planet after the Empire collapses and it gets sacked), but in the prequel novels it's described as a very diverse planet -- so diverse that Hari Seldon uses it as a sufficiently simplified model of the galaxy for Psychohistory.

Live Action TV

 * Star Trek
 * Voyager
 * This is the unofficial In-Universe explanation for Tuvok's skin color -- he's from a different stock of Vulcan than most of the ones we've seen. And Tuvok wasn't the first "minority" Vulcan we've seen. At least one of the Vulcan priests seen at the end of Star Trek III: The Search For Spock highly resembles an Asian person from Earth (which makes sense, as the Vulcan in question is played by George Takei, who had apparently always wanted to wear the ears, but never had a chance up until then).
 * There was this one episode where Chakotay, on his own on a planet, joins a group of humans in an effort to overthrow the lizard-people on the planet. It's two separate regions, two separate cultures. However, the two cultures (Vori and Kradin) are, at their worst, at least equally corrupt and brutal, and at their best equally welcoming, or so it's implied. It's even suggested their customs are similar--they seem to share at least one tradition. So it's a bit of a subversion, really; the two are different, certainly, but ultimately not by that much. We might even go as far as to say Vori-Kradin does have a unified culture under default settings, only it's in a state of civil war at present...
 * In the Star Trek Deep Space Nine relaunch novels, the Andorians and Bajorans, at least, demonstrate significant cultural differences depending on which region of their planets they originate on. In Worlds of Deep Space Nine: Andor, the differences between Northern and Southern clans (to oversimplify a bit) are an important aspect of the plot. We also learn that "Bajora" originally referred to one nation on Bajor that over the civilization's very long history grew to encompass all Bajorans. The relaunch also explains the differences between Next Generation and Deep Space Nine Trills (ridges vs. spots, transporter allergy, etc.): they're just different ethnic groups among the Trill humanoids. Star Trek: Enterprise adds the Aenar (blind telepathic pacifist albino Andorians) to the list of Andor(ia)'s native ethnicities.
 * In Star Trek: Articles of the Federation, the funeral service for former president Jaresh-Inyo references his culture as "semtir"--his species is Grazerite, but apparently not all Grazerites have the same customs.
 * The Next Generation has an episode involving a planet on which the population is divided into two different factions, who are caught up in a cold war.
 * The Original Series
 * The episode "The Omega Glory" involves a war between two cultures living on the same planet, descended from cultures very similar to Cold War era Americans and Russians.
 * In another TOS episode ("Let That Be Your Last Battlefield"), there is a war between two different ethnicities from the same planet. (The skin of one is black on the left side and white on the right side of the body, the other one's skin white on the left and black on the right.)
 * In the Doctor Who serial "The Keys of Marinus", the protagonists visit a different area of Marinus in each episode, each with its own inhabitants and culture.
 * The Fourth Doctor serial The Face of Evil involve the Tesh and Sevateem (Leela was one of the latter), two orthogonally distinct cultures (technologists and savages) on the same planet. Of course, they both originated from the same initial culture over 9000 years earlier.

Video Games

 * The quarian species in Mass Effect were originally represented in the first game by one individual, who spoke with a suspiciously Eastern European accent. In the sequel, we are introduced to multiple other quarians. While some share the Eastern European accent of the Token Minority party member, others possess more distinctly British or American accents, and one of them is quite clearly Adam Baldwin. Clearly, the population of the quarian flotilla is drawn from many elements of the species, and each ship has its own subculture.
 * The Codex suggests that most species still maintain multiple languages, even after however many centuries of interstellar travel. By this point, technology has evolved such that subdermal devices instantly translate other languages into the listener's own, and most everyone seems to have one. That said, quarians are pretty much the only non-human species encountered that have a discernible accent; everyone else (besides Miranda) speaks in a generic North American accent, no matter what language they're speaking or species they belong to.

Tabletop Games

 * In Traveller, the Aslan are divided into many different clans with their own parochial customs. The Vargr have no rhyme or reason to their organization, being Chaotic Neutral.

Web Comics

 * In Quentyn Quinn, Space Ranger the titular character once informed the Worf stand-in just how inaccurate his idea of his own species was.
 * In Dominic Deegan, crossing over with Our Werewolves Are Different, the people of the Winter Archipelago have several different subgroups--werewolves vs. spellwolves, the nobility vs. commoners, young vs. old. When Mookie had one storyline focusing on the nobility, followed by another storyline focusing on their equivalent of wild college kids, he was accused of being "inconsistent" when it was really this trope.
 * The Cyantian Chronicles: Cyantia is inhabited by at least a dozen different species, both natives and immigrants created from human and animal genes. The immigrants compose four major nations (the Mounty Kingdom, the Alpine territories, the Wolf City-States, and the Fox Empire) and numerous less powerful ones. The natives tend to keep to themselves.
 * The Trolls of Homestuck have pretty diverse culture, based even on the small sampling that we actually get to see.