The former Shipping Corporation of Polynesia's chief executive, New Zealander John Jonesse, has been jailed for five years for his role in the sinking of the Princess Ashika.
74 people died when the ferry sank in 2009.
Four men and the company were convicted on 30 counts on Friday, including one each of manslaughter by negligence in relation to the death of Vaefetu'u Mahe, whose body was one of just two recovered after the sinking.
The former director of marine, Viliami Tu'ipulotu and Jonesse were also convicted of sending an unseaworthy ship to sea on five occasions, while the skipper, Maka Tuputupu was convicted of taking an unseaworthy ship to sea five times.
Jonesse was also convicted of forgery and knowingly using a falsified document.
Tu'ipulotu was given a three-year suspended sentence.
Tuputupu was given a four-year jail term but will only have to serve six months of it while the first mate, Semisi Pomale, got a five-year jail term but has to serve just 18 months of that.
The Shipping Corporation of Polynesia has been ordered to pay just over one million US dollars in fines.