Yousuf Yaqoob, Mohamed Saleh, Yakoob Ibrahim, Saleem Muhammad, Bhatti Abdul Ghafour, Baksh Moula, and Pak Abdolghaffer were charged with the crime.
The prosecution said the drug was in two consignments: 377.2 kilograms of heroin valued at Sh1,131,672,000 and 33,200 liters of heroin worth Sh189 million.
"We have been sentenced to die in the Kenyan prisons. The court should have taken into consideration our elderly age and nine years we have spent in prison," said Saleh.
He added: "We have been abandoned to die here and we have not seen our families for years."
Senior Prosecutor Alexander Muteti said the court exhibited boldness by imposing a maximum sentence as this will deter trafficking of narcotics through Mombasa.
While sentencing them Mutuku also fined the six Pakistanis and an Iranian Sh3.9 billion each or serve one year in prison.
"I hereby sentence the seven accused to life imprisonment and also to pay a fine of three times the value of the drugs over Sh1.3 billion," said Mutuku.
She said the convicts failed to exonerate themselves and reveal the owner of the said drugs, adding that the court placed a special emphasis on the transnational nature of the crime and the value of the drugs.
"The court places special emphasis on the transnational nature of the crime. Even as the court sympathises that they have been in custody for nine years and are sick and elderly the court has come to the conclusion the custodial sentence is not appropriate given the nature of the crime," said Mutuku.
In her judgment Mutuku said the prosecution produced enough evidence to convict the crew members and proceeded to convict them.
The seven had been hired as crew members for Armin Darya Said's vessel that was intercepted in the Indian Ocean by American operatives in 2014 and later blown up at sea under the supervision of former President Uhuru Kenyatta despite existing High Court order to preserve the same as a court exhibit.
During an earlier court hearing, the crew told the court that they were transporting cement from Iran to Zanzibar.
Mutuku said the fact that the vessel's GPS was off proved that the crew was up to something as they didn't want to be located.
"I find the crew members culpable. They can't say they didn't know of the said narcotics. The vessel's GPS was off and the drugs were well concealed and they didn't exonerate themselves by telling the court the ship's owner and who sent them," said Mutuku.
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Yousouf Yacoub, the assistant captain told the court that the owner of the vessel was Ibrahim Haji and that they were contracted for three months and were to be paid after delivering the cement.
The seamen through their lawyer Sharon Maiga asked the Mombasa court to consider their age and the 10 years they have spent in custody when convicting them.
"We are appealing for leniency and consciousness of the court in sentencing them. Each of the accused is remorseful and pray to be reunited with their family. In their defense, they said they were sorry and we pray the court take judicial notice they are paupers and if they were to be subjected to three times the value of the drugs, that would be sentencing them to life," said Maiga.
In mitigation, Maiga asked the court to consider rehabilitation as opposed to the life sentence that the prosecution had pleaded for.
She said the youngest among the accused is 65 years, while the oldest is approaching 80 and unable to walk and the status of his health is deteriorating.
"We are appealing to sense of humanity in sentencing the accused. In sentencing of elderly persons, it could amount to slow death."
She said the accused have family members who they have not seen for nine years and have been isolated and mentally affected including being denied visitation.
"They have sufficiently been punished with the period in custody," said Maiga.
In his submission, Muteti asked the court to impose life sentence regardless of their advanced age terming the offence serious.
He urged the court not to place too much faith on age because when the accused proceeded to traffic the drugs they were fully aware that they were aged.
"Their age notwithstanding the message must be drawn that he who engages in this trade must be ready to pay the price. Impose a custodial sentence and give a fine," said Muteti
He said the offences are very serious considering the amounts of drugs recovered and potential effect they would have had, had the drugs been released into the market.
However, Mutuku acquitted three Kenyan shipping agents - Khalid Mohamed, Mohamed Osman, and Maur Bwanamaka - for lack of sufficient evidence to prove that they were in any way involved with the shipping agencies or were aboard the said vessel.