Three of the five have been charged with possessing “false identity documents with improper intention” under the Identity Documents Act.
Police named them as Orlin Roussev, 45, Bizer Dzhambazov, 41, and Katrin Ivanova, 31. They are all Bulgarian nationals.
The BBC reported they have been accused of spying for Russia.
They have been remanded in custody and are yet to enter pleas. They will appear at the Old Bailey at a later date.
They were among five people who were arrested as part of Official Secrets Act investigation in February. The other two were released on bail and must return in September. The investigation continues.
The investigation is being led by the Met's Counter Terrorism Command.
According to the BBC, the three people have allegedly been living in the UK for years, holding a succession of jobs and living at various addresses.
One of them is said to have a history of business dealings involving Russia, while the other two, described as a couple in the BBC report, ran a community group providing services to Bulgarian people, which helped familiarise them with the “culture and norms of British society”, according to the report.
The report alleges the couple also worked for electoral commissions in London which facilitate voting in Bulgarian elections by citizens living abroad.
Police declined to comment on whether they were suspected of being Russian spies.
Britain has been sharpening its focus on external security threats and last month it passed a new national security law, aiming to deter espionage and foreign interference with updated tools and criminal provisions.
The government labelled Russia “the most acute threat” to its security when the law was passed.
Since 2018, police have charged three Russians, who they say are GRU military intelligence officers, with the 2018 attempt to murder former double agent Sergei Skripal with the military-grade nerve agent Novichok. Two were charged in 2018 and the third in 2021.
Last year, MI5 director general Ken McCallum, Britain's domestic spy chief, said more than 400 suspected Russian spies had been expelled from Europe.
Britain has also been one of the strongest supporters of Ukraine since the Russian invasion last year and has imposed a range of sanctions on Russian officials and oligarchs.