Jermaine Grant, from London, was jailed for nine charges related to trying to illegally obtain Kenyan citizenship.
Grant was earlier this year acquitted of the charges, but a high court judge in Kenya overturned the decision.
He is also facing charges of “conspiring to improvise an explosive device” and a trial is continuing. Grant denies the charges.
Grant was arrested in 2011, when batteries and chemicals were discovered in his apartment in Mombasa.
UK police – who have provided forensic assistance to Kenyan authorities – allege they were “precursors for making highly volatile explosive substances”.
Samantha Lewthwaite, known as the “White Widow” and wanted in connection with the 7/7 bombings in London in 2005, is also suspected of being involved in the alleged plot.
She escaped arrest in Kenya in 2011 and has been missing since then.
The sentencing of Grant comes after Mombasa High Court judge Martin Muya overturned an earlier acquittal on the Kenyan citizenship charges.
He sentenced him to one year in prison for each of the charges.