I am writing something set in the Victorian era and I want to make sure it is accurate/plausible. Would a British anthropologist (a lone scientist with no intentions of conquest) have been allowed into German East Africa in the 1880s? I don't fully understand which European power (if any) dominated the Zanzibar coastal region prior to German East Africa. Would a British man have been welcomed into the Sultanate of Zanzibar in the 1870s? How about Portuguese Mozambique during this era? When I say "welcomed" I mean been allowed by local authorities to conduct an archaeological dig and investigation in the area.
If we are talking about the 1880s, I think it is entirely fair to ask: who is going to stop them?
That is to say, between 1885-1890 German East Africa (and the Congo Free State and many other colonies) were very much ad-hoc affairs where German influence was only felt where Carl Peters had established fortresses or where he and recruited Askaris could be found.
More plausibly, a British anthropologist who made it to Zanzibar (which was nominally independent but moving towards becoming a British protectorate in 1880s) in 1886-1889 with scientific goals would try to link up with an Arab-Swahili caravan heading towards Buganda (in modern Uganda), the Congo basin or towards Katanga (as missionaries like William Francis Arnot or Dugald Campbell had done).
Again, 1880s and even the early years of 1890s is really too early for German East Africa Society to establish any sort of administrative control or customs/border controls over entry into territory they claim as German East Africa. So, as long as a British anthropologists does not come across a German column, he would be much more concerned about receiving a positive reception from the local African rulers that his caravan comes in contact with.
Now, I'll add a long aside about the case of Major Emile Storms and the fortress at Mpala on the eastern shore of Lake Tanganyika in 1883. Storms was a Belgian officer in the employ of the International African Association that was a front for king Leopold's Congo Free State colonization effort. He left Zanzibar in 1882 with two German subordinates, Bloehm (a scientist) and Reichard, and reached an already-established IAA settlement at Karema called Fort Leopold in 1883.
While at Karema/Fort Leopold, Storms left Bloehm in charge of the fort while he led askaris against a local chief named Chata which had been raiding villages in the region.^1
There is more to the story of Storms and Reichart, but I think this episode is enough to convey the sense that in the early 1880s in East/Central Africa, European national distinctions were not a priori a cause for mistrust. Germans, Canadians, Brits and Americans worked in the Belgian colonial project in the earliest days.
1- Dance of Assassins by Allen F Roberts. Roberts is primarily interested in Storms' expedition against the Sanga warlord Lusinga lwa Ng'omba and what it entails for early-colonial authority/power in Congo.
My experience is with territories claimed by France, but the short answer is no, you would not be welcomed if you just showed up and started doing archeological work.
Indeed the French Colonial Archives are chock full of people requesting permission to do scientific (and some archeological) studies in French colonies. There is a pretty big pattern to the MIS series, a letter of introduction and request are sent, these more often than not come from Frenchmen, but there are plenty from England, Germany, Japan, US. There is then cross-government inquiries about whether the mission is legitimate and whether it has a chance at success (typically random people with no prior scientific training or travel experience get politely denied). Inquiries are also sent to the nearest French embassy to the applicant and the colonial governor assuming the application passed an initial screening. The embassy might be asked about the moral character of the individual (are they really coming in to rob the colony of treasures or agricultural secrets or are they a spy or tied to criminal enterprises or particular missionary activity). The local governor might also be asked if they are aware of this individual, given a summary of their request, and asked for their thoughts on the matter if it was worth approval or if the state should/had any funds available to assist.
I have not gone through the entire MIS series, that would be an intense project, but more often than not, the folders in the archival cartons are just one or two pieces or correspondence that end in rejection.
Government authorities were not keen to allow someone to just wander into the jungle or an isolated island and get trapped there, possibly expecting rescue. They wanted to be sure someone had the means to make it on their own and contribute something of value.
Being tied to a museum or university certainly gave an aura of legitimacy to your mission. Made it more likely that you would have knowledge of the region, a solid plan, good support stuff, and enough funding.