In the first ruling of its kind in Italy, the six Eritreans were given prison terms ranging from two years and four months to six years and three months, Il Tempo reported.
The ruling was made in a fast-track trial, meaning it can not be appealed.
The trial stemmed from an investigation, called ‘Glauco 1', which was launched after the boat tragedy.
The heaviest sentence was handed down to 27-year-old Samuel Weldemicael, who was given six years and four months, followed by 25-year-old Mohammed Salih, who got six years.
The court also sentenced 31-year-old Nuredin Atta Wehabrebi to five years; Tesfahiweit Woldu, 26, to four years; Yared Afwerke, 25, to two years and eight months, and Atywos Melles, 48, to two years and four months.
The six were convicted of racketeering and abetting illegal immigration. Three other defendants, believed to have been the leaders of the human trafficking ring, are still at large.
The overcrowded boat is thought to have capsized after one of the smugglers lit a fire on board to alert the Italian coast guard to their whereabouts, sparking panic among the hundreds of passengers.
Italy vowed to crack down on human traffickers in the wake of the tragedy, with investigators building their case around survivor testimonies and 30,000 wiretaps, which included conversations among the smugglers about the deaths of their passengers.
In one intercepted conversation, they blamed the migrants for the tragedy, "because they wanted to leave in great numbers".