Kira Yarmysh, his spokesperson, posted on X that a service for Navalny would be held on Friday at 1400 Moscow time (1100 GMT) in the Church of the Icon of the Mother of God in the Moscow district of Maryino where Navalny used to live.
Navalny would then be buried at the Borisovskoye cemetery, which is located on the other side of the Moskva River to the south, Yarmysh said.
Such services, presided over by a priest and accompanied by choral singing, usually allow people to file past the open casket of the deceased to say their farewell. The chosen Russian Orthodox church is an imposing five-domed white building in a built-up suburb of southeastern Moscow.
It was not immediately clear how the authorities would ensure crowd control.
But judging from previous gatherings of Navalny supporters - whom the authorities have designated as U.S.-backed extremists - a heavy police presence is likely and the authorities will break up anything they deem to resemble a political demonstration under protest laws.
Navalny, 47, died at an Arctic penal colony on Feb. 16. His allies have accused President Vladimir Putin of having him murdered because the Russian leader could allegedly not tolerate the thought of Navalny being freed in a potential prisoner swap.
They have not published proof to back up that accusation, but have promised to set out how he was murdered and by whom.
ACCUSATIONS
The Kremlin has denied state involvement in his death and has said it is unaware of any agreement to free Navalny prior to his death.
Navalny's death certificate, according to supporters, said he died of natural causes.
His mother last week accused the authorities of trying to blackmail her into holding a private funeral for her son by initially withholding his body, an assertion the Kremlin called absurd.
Navalny's allies had been looking for a hall to accommodate his supporters at a farewell ceremony, but said they had been refused everywhere.
"Initially we planned the farewell and funeral for February 29th. It quickly became clear that there was not a single person who could dig a grave by the 29th of February," Ivan Zhdanov, a Navalny ally, wrote on X.
Feb. 29, Thursday, is the same day as Putin is due to deliver a speech to Russia's political elite and Zhdanov accused the authorities of not wanting Navalny's funeral to take place on the same day and overshadow it.
Zhdanov also accused the authorities of blocking attempts to secure a large hall for supporters to bid farewell to Navalny.
"Bxxxxxxx. They won't give us the date we want. They won't give us the hall. Everyone will say goodbye to Alexei anyway," wrote Zhdanov, who is outside Russia.
The Kremlin has said it has nothing to do with arrangements concerning Navalny's body.
