In a sombre procession, some of the 73 students, wearing white and black uniforms and carrying book bags, bowed their heads as they cried and walked slowly from a bus to the entrance of Danwon High School in Ansan, outside of Seoul.
Some stopped to hug the parents of their friends, while a large banner reading, "We pray the dead will rest in peace", was hung up on the school entrance gate.
The anger, grief and deep remorse at the school was a reflection of what many South Koreans have felt since the April 16 sinking that left more than 300 people dead or missing. Of the 325 students on a class trip to the southern holiday island of Jeju, 75 were rescued, 245 died and five are still missing. Two of those rescued had already returned to school.
The return to classes of the survivors, who had been staying at a facility in Ansan where they had classes and therapy sessions, comes amid court hearings for the ferry crew and the officials from the company that owned it.
Many South Koreans also fault the government, the coastguard and even society for failing the victims.
The government of president Park Geun-hye, whose dictator father ruled during the economic boom in the 1960s and 1970s, has been battered by criticism it should have done more before the sinking on safety and monitoring issues and that its incompetence botched the rescue operations.