He faces 18 to 24 years in jail if convicted of the murder and a further eight-and-a-half to 18 years for belonging to a terrorist organisation.
The prosecution did not seek a life sentence for Samast as he is classed as a minor by the Turkish court. His age also means the trial is closed to the public.
|More than 100,000 people took to the streets |
of Istanbul on the day of Dink's funeral [EPA]
Two other men, Yasin Hayal and Erhan Tuncel, are accused of ordering the murder and being the leaders of a far-right group.
They could be jailed for life without the possibility of parole if found guilty.
The 15 others on trial face jail sentences of between seven-and-a-half and 35 years.
Fethiye Cetin, the Dink family lawyer, told a news conference that she believed several unnamed security officials should also stand trial as they had links with the suspects.
"Members of the security forces - in Trabzon, where the killing was planned; in Istanbul, where it was executed; and in Ankara, where the intelligence was gathered - were not included among the accused."
"And this despite the established fact that they had links with the suspects, failed in their duty, concealed evidence and even sought to vindicate the murder and the murderer."
'Test of independence'
Human Rights Watch, the international rights organisation echoed the lawyer’s opinion, saying in a statement that "Hrant Dink's murder trial is a critical test of the Turkish judiciary's independence."
"The Turkish judiciary must hold accountable any security forces responsible for negligence or collusion in the murder."
Dink, 52, is believed to have angered the Turkish far right after openly arguing that the mass killings of Armenians in the dying days of the Ottoman Empire between 1915 and 1917 constituted genocide - a label Turkey officially rejects.
The murder sent the country into prolonged shock, and more than 100,000 people took to the streets of Istanbul on the day of Dink's funeral, chanting "We are all Hrant Dink" and "We are all Armenians."