The overloaded ferry Sewol had capsized while making a turn on a routine voyage to the holiday island of Jeju.
Read MoreSafe waters but Korean ferry may have been going too fast
Video footage of the crew abandoning the vessel after instructing the passengers, mostly teenagers, to remain in their cabins caused outrage across South Korea and calls for harsh punishment.
The court found all the remaining 13 surviving crew members guilty of various charges, including negligence, and handed down prison terms ranging from five to 20 years.
Read MoreScenes from South Korea's ferry disaster
Anger and grief gripped the nation after its worst maritime disaster in decades, and President Park Geun-hye's government was heavily criticized for what was seen as a botched rescue operation.
Only 172 of the ferry's 476 passengers and crew were rescued. Of the 304 confirmed dead or still listed as missing, 250 were school children.