The businessmen were found in a bus by Kenyan security officers who had been trailing them.
The drugs weighing 30 kilogrammes had been packed in three suitcases, according to latest media reports from Kenya.
Anti-narcotics unit head Khamis Massa said the suspects were taken to Port police station in Kenya.
The three are among wanted drug dealers in the region.
The covert operation that led to their capture was conducted by a multi-agency team of the Kenyan Directorate of Criminal Investigations (DCI), National Intelligence Service (NIS) and anti-narcotics sleuths.
"We are interrogating the suspects, whom we believe are drug traffickers, to establish where the drugs were destined for," Massa said yesterday.
Like Kenya, Tanzania is among African countries used as transit points for hard drugs.
Last year, officers seized drugs worth 10 million Kenyan shillings and arrested 12 suspects, among them Tanzanians, in Mombasa.
The Kenyan government has recently deported several drug barons including Italians in the war on drugs.
There has recently been a spike in reported cases of high-profile arrests of Tanzanian nationals abroad for drug trafficking.
Officials from the Tanzanian Drug Control Commission (DCC) were yesterday not immediately available for comment on the latest arrest.
In August last year, a Tanzanian woman was among two suspects arrested in New Delhi, India, with a huge stash of cocaine worth around 14 billion Tanzanian shillings.
The woman, a 40-year old Tanzanian national identified as Beatrice K. Ndyetabula, was arrested at the Indira Gandhi International Airport.
The other suspect arrested in the bust was identified only as Augustin (33), a Nigerian male.
Indian anti-narcotics officials said Ndyetabula landed in Delhi from Mumbai and, when intercepted and frisked in the terminal area, 27 ribbon rolls concealing four kilogrammes of cocaine powder were recovered from her hand baggage.
Back in February last year, President John Magufuli personally ordered local security forces to launch a comprehensive crackdown on illegal drugs trafficking in the country, sparing no one including top politicians and their relatives.
Magufuli's drive against illegal drugs reflects growing international concerns that East Africa is being used by traffickers.
For example, while most Europe-bound heroin from Afghanistan is known to go through Iran and the Balkans, a spate of record-size hauls near Kenya and Tanzania has raised fears that East Africa is seen as an easier route because of porous borders and weak maritime surveillance.
Security sources say the African continent is geographically situated between opium production and consumer states, allowing heroin to reach Africa via multiple heroin trafficking routes originating in Afghanistan where the overwhelming majority of global opium is produced.
The route goes through Pakistan and Iran to their coastlines, known as the Makran Coast. From there, the drug is loaded onto dhows which cross the Indian Ocean to transit states in either Africa or Asia, from where it is rerouted to its final destinations, mostly in Europe. The second phase of the journey can be by sea, land or air.
The dhows are large vessels often used for fishing explorations and able to undertake long journeys.
To avoid detection, the dhows either dock at island ports or remain out at sea. The heroin is then collected by smaller boats and taken ashore.