China, in common with other East Asian countries, has boat-dwelling ethnic communities. One such group, The shuǐshàng rén (水上人) sometimes appear reductively in Western sources as ‘Sea Gypsies.' They are also referred to by the derogatory appellation Tanka (疍家 or Dànjiā). Better labels in English are the ‘On-Water People’, ‘Boat People’, or ‘People of the Southern Sea.’
Other such groups in China include Hoklo/hokklo/hokkien boat people (Though only some Hoklo were boat people) and the "Fisherfolk of the nine surnames" in the North.
These Boat dwelling communities were not necessarily 'nomadic.' Some moved between anchorages, some stayed in fairly constant movement around river systems or particular estuaries, while others remained fairly permanently in the same urban anchorage or general area. The three major areas of boat-living in China were Shanghai, the Yangtze watershed, and the rivers/coasts of South China.
The 'On-water people' have a history stretching back many centuries, though their precise genealogy and anthropological origins are disputed. The most common theory is that they descend from Yue inhabitants of Guangdong forced off their land by Han settlers during the Song Dynasty (960-1280 CE). They lived in boats and typically made their living from fishing or other maritime activities.
It should be noted that this process of dispossessed land-dwellers forming or joining maritime communities was not limited to the Song dynasty. Boat-dwelling as a response to precarity continued well up to the modern period. So while boat-dwelling was associated with certain ethnic groups in particular, boat-dwellers could be anyone. The extensive canal and river systems of central China motivated many families and residents to resort to living in houseboats to escape high rents. These itinerant populations might scrape a living fishing, operating their boat as a ferry, gathering shellfish, begging, practicing a craft, or operating small market stalls from their boats.
As taxes were generally land-based, and crafts were often regulated; boat-dwelling communities tended to face prejudice from land-dwellers, guilds, and local officials. Some areas and officials sought to exclude water dwellers by way of laws and regulation, or by turning a blind eye to popular violence against them. The Government attempted to tax boat-dwellers through household registration, and later to control piracy and movement through boat registration. But these attempts were sporadic and seem to have been mostly unsuccessful.
In addition to being targets of popular violence, water-dwelling communities were often at heightened risk from fires, floods, typhoons, or other natural disasters. Even in the 20th century, Boat dwelling people of Hong Kong suffered enormous devastation from Typhoons. In the late imperial period, the Anchorage outside Guangzhou (广州市, Canton, or Kwangchow) was described as an almost solid mass of boats 200 feet wide and stretching for six or seven miles. It was the site of terrible fires in which several hundred boats could burn and hundreds or even thousands might die.
Boat dwelling was also tied to other characteristics than ethnicity. River captains typically lived onboard a boat or ship with their families in pre-industrial China. Guangzhou notably had a large boat community composed of those suffering from Leprosy, which anchored somewhat separately on the river. Sex workers also often lived on 'Flower Boats' anchored in the river in Guangzhou and some other places. Those who worked the small ferries or water taxis of Shanghai reportedly often lived in their boats with their families.
I should also note that these classifications were somewhat porous, boat-dwellers sometimes settled on land in the same way land-dwellers sometimes took to boats. On land, former boat-dwellers tended to be 'shed people' without title to land, experiencing a similar quasi-legal and precarious existence. This was particularly true of the Shuishang Ren, who faced high levels of discrimination regardless of where they lived. The general poverty of these groups also had exceptions, as some families were able to become quite wealthy from fishing or shipping. Periods of instability and dislocation such as the Ming-Qing transition also provided opportunities for people to change their status or reinvent themselves.
Outside of China, other Asian groups to look into for those interested include the Iranun, Sama-bajau/Balangingi/Bajo, Moken/Mawken, and Orang-Laut.
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I'd say Oceanians if we're talking about mainly travelling through water. They weren't specifically living on their double-hulled canoes but they spent most of their time on it. They were one of the greatest seafaring culture that ever existed. They've colonised the islands of the Pacific, a lot of which weren't reached by man before them. Austronesians (3000BC-1000BC) left south-east Asia (evidences suggests Taiwan) to reach the Philippines and so on always going further East. They progressively developed a culture named the Lapita culture which was distinguished by distinct dentate-stamped pottery who was spread around a large area.
They reached Micronesia and Melanesia, mixing with the people that were already there but after landing on Vanuatu I think it was the beginning of discovering islands that were devoid of human presence. Until the Lapita reached the islands of Samoa and Tonga (around 900 BC) they've abruptly stop to go east and will stay here until the migration start again (around 700 AD). During this long period the Lapita culture will disappear and what we called the Ancestral Polynesian Culture has rose. They will leave to discover and colonise the rest of the Pacific islands French Polynesia and Cook islands (Rarotonga) at the center Hawaii up north, Easter Island (Rapa Nui) far east and finally New Zealand (Aotearoa) who was the last island to be reach by the Polynesians (around 1200 AD).
What was amazing to know was their knowledge concerning seafaring. Using their environment as a compass. During the day it was shape of clouds, shape of waves, winds, ocean currents, birds, the sun. And at night they used the stars (they had a litteral map of stars on which they could identify the right one to follow in order to reach a specific island and they memorized them all). Anyway, my description doesn't do justice to how savant they were and I didn't talked about how efficient their canoe were (double-hulled or outrigger canoe) praised by Europeans navigators like Samuel Wallis, Louis-Antoine de Bougainville, James Cook and many others.
Thanks to the research of Archaeology/Anthropology/History/Linguistics...we can grasp a fraction of what this amazing culture left us. If you want to know more you can read the research of Patrick Kirsch, Yoshi Sinoto (the only main english scientific researcher I can remember)
Many Norwegian travellers lived in boats, moving along the coast from harbour to harbour. They were collectively called "fant", but were made up of a mix of several Rom-speaking peoples and Scandinavian and German speakers.
Their early recorded history consists of hostile or derogatory folklore, unsystematic observations by early sociologists like Eilert Sundt, and the records of the forced assimilation efforts of the Norwegian state, but this subculture of the travellers persisted into the 50's and 60's.
Hopefully, now that traveller culture is being recognised and some efforts toward reparation made, more records will be made and popularised before the oral history of this phenomenon is lost. In trying to give an impression of it, I risk repeating racist and classist myths and the misconceptions of outside observers simply because that's what's readily available. But Gunvald Opstad's "Utav Reisendes Folk" (From Travelling People, 1986) Interviews actual boat travellers from the southern coast: https://www.nb.no/items/6e4909a4fa292f1c6e87028836c8e916
Sources disagree on the "ultimate origin" of this group - on one hand some spoke creole Rom languages that could date their arrival in Norway to the 1500's, on the other hand many were descendants of Scandinavian and German people displaced by poverty, health issues or social ostracism. Young people ran away to join the fanter; tenant farmers married fanter and absconded. In a society of strict social control and a very high value placed on belonging to a farming community, the fanter was an escape opportunity and a category marked miscellaneous for anyone who didn't fit in. These days, this origin debate is mostly just a demonstration of the inadequacy of nationalist or racist origin stories when applied to the messy reality of living culture.
The Norwegian coast is a maze of skerries, peninsulas and fjords. As traveller groups were persecuted both officially and unofficially, the "skjærgård" - skerryhome - must have seemed attractive. Traveller groups were forbidden from staying anywhere more than two days, and inland Norway was mostly wilderness. But along the coast, you could and still can tie up a boat anywhere if you know the waters well enough, bypassing dangerous and poor roads and isolated inland communities that were rumored to attack strangers on sight. Most "fanteskøyter" were small, old vessels at the end of their useful life, bought cheap or salvaged, though accusations of theft followed travellers everywhere.
These family run boats would travel between coastal communities, asking for work and offering services like mending and fortune telling, much like their land-based colleagues. It was a precarious existence, and the choice of sticking to the coast rather than the roads may have simply traded one set of dangers for another. While many followed set annual routes, there was no guarantee that people would welcome the "patched sails" every time they appeared, and coastal communities in the past three centuries had an increasingly unequal distribution of wealth, changing local upper class views of the travellers from labour resource and diversion toward a public burden.
The boat traveller culture suffered the same systematic destruction as other Norwegian traveller cultures, starting with workhouses, prisons and state abduction of children in the 1850's to racialisation and medicalisation enabling genocidal strategies imported from the European colonies. Forced settling, boarding schools and psychiatric "treatment", including forced sterilisation and lobotomies took place in the period from 1900 into the 1970's.
Descendants of many different traveller groups are now advocating for their inclusion rather than assimilation in Norwegian society, but as far as I'm aware there are no more boat travellers - for now.