The move is considered controversial as Tanzania has not published figures of Covid-19 cases in months.
The two East African nations have been locked in a diplomatic standoff since May when Kenya blocked Tanzanian truck drivers from entering the country.
The Kenyan government had long feared that its neighbour was not transparent on how it dealt with the pandemic. In June, President Magufuli declared Tanzania was “coronavirus free” thanks to prayers by citizens.
But the tension seems to be cooling off now.
Other countries whose travellers Kenya has exempted from mandatory quarantine include South Africa, the US, India, Mexico and Spain – who are among countries with the highest Covid-19 cases in the world.
The Kenyan authorities will still require all arriving travellers to have a Covid-19-free certificate. Passengers with body temperatures above 37.5 degrees will be quarantined.
Kenya has more than 36,000 confirmed cases of Covid-19 and more than 600 deaths.