Odinga left the country on Sunday evening.
Mtanzania, one of the leading newspapers in Tanzania, quoted its sources who had spotted Odinga at a small restaurant in Old Town Zanzibar Island.
The Opposition chief had managed to keep his Tanzanian trip very private unlike his recent tour to the United States which was highly publicized.
The Tanzania newspaper indicated that Odinga appeared to be on a private holiday based on his light entourage that only involved a bodyguard and one aide.
“I saw him and he was with his assistant and one bodyguard as they entered Lukmaan for lunch,” the witness was quoted.
The report appeared to corroborate an earlier statement by Odinga’s long term-advisor, Salim Lone, who had spoken to the New York Times while in London, claiming that unrest forced Mr Odinga to fly to Zanzibar.
"The unrest pushed Odinga out of the country. He left Kenya and is now in Zanzibar, off the coast of mainland Tanzania,” Lone stated.
The former Prime Minister had landed in Nairobi on Friday and was welcomed in a chaotic procession that left five people dead.
On Sunday, Odinga appeared in Ruaraka where four people had been killed in mysterious circumstances, and quietly left the country the same evening.
The Supreme Court of Kenya would later on Monday uphold the election of Uhuru Kenyatta as President.
Odinga, in statement released by Lone, dismissed the Supreme Court ruling stating that it did not change NASA’s position that the Jubilee government is illegitimate.