The coming-of-age theme is important in Lord of the Flies precisely because almost none of the boys successfully go through it. Only Ralph makes real progress toward adulthood. If the rescue had not come when it did, they soon would all have killed each other.

Many of the group's difficulties are caused by their youth and inexperience. They are simply unable to grow up as fast as they need to in order to survive. Their failure to cooperate is identified with childishness. Those who succeed at hunting refuse to share or to value others' contributions.

Jack, who is the least mature of the boys in his age cohort, cannot grasp the meaning of leadership; he is mainly interested in adulation. His immaturity costs two boys their lives.

Piggy makes some progress in maturing, but his opportunities are cut short. His stubborn, inflexible personality is also ill-suited to the circumstances. Had he not fallen victim to resentful bullies, he would have continued to counsel Ralph and might have gained some insights into political behavior.

Ralph succeeds in staying alive despite Jack's persecution because of his personality and because he is mature enough to process information quickly and analyze difficult situations. His abilities improve through the course of the novel, although he suffers some setbacks, including the loss of his friends.

Because Golding ends the novel at the point the boys are rescued, the reader does not learn the impact of the experience on the next stage of their lives. Perhaps reflection in the safety of their homes will help them take the next, positive steps toward maturity.

Lord of the Flies can be seen as a coming-of-age story—albeit a rather unconventional one—in that it details the transition from boyhood to manhood and the loss of innocence that this process entails.

When the boys first wind up on the island, they're still recognizably children. Yet in order to survive, they need to grow up pretty quickly, taking on the kind of responsibilities—building shelters, hunting for food, forming a kind of government—normally associated with adults. In the process, they lose their innocence and find themselves thrust into a world of bloodshed, terror, and violence.

Although all of the boys are mature to some extent, the level of maturation isn't spread out equally among them. Ralph is more mature than most of the boys right from the very start, whereas Jack still displays signs of arrested development in his character. He may well establish himself as the absolute ruler of the island, maintaining control through terror and violence, but there's still something childish about his impulsive behavior.

The Lord of the Flies is certainly a coming of age story, even though it occurs within a very limited time frame, and doesn’t follow the boys into adulthood. A coming of age theme is usually present in a text through several markers:

A loss of innocence: this is seen clearly when the boys lose their humanity in a tribal dance, and in their hysteria, murder one of their own. The death of Simon marks a significant turning point in the novel, since it’s the first death that occurs at the hands of other boys, rather than as an accident or a result of the crash.

Questioning authority: Many of boys question Ralph’s authority, though Ralph was almost unanimously elected at the start of the novel. Though they frequently wonder what grown-ups would do in their situation, most of the boys reject any attempt at structure in order to spend their time hunting instead.

Rebelling against society: The loose society they set up for themselves is quickly dismantled by Jack’s insubordination and subsequent tribal takeover.

And finally, if you want to get really depressing, Ralph especially experiences the truly adult acceptance of one’s futility to change society in meaningful ways. (This is an admittedly nihilistic read of the text.) He can’t turn the tide back to his authority, can’t convince the boys that there is no beast, and can’t save his friend Piggy. In the end, the Captain that rescues them is like a disappointed father, scolding children. While the boys came of age and lost their humanity, in the end, they are still little boys.

One of the major reasons that Golding wrote The Lord of the Flies was to present a picture of what would happen if innocent boys were placed on an island alone without the influence of society or rules or adults. This also gives them the opportunity to "come of age" without those same influences and his novel was intended as an examination of how that might work.

In this case, the conclusions of this study are not very optimistic given that the boys struggle mightily with the idea of social order and justice and, just before the boys are rescued, it appears that they have grown up to become savage and brutal. Rather than listen to the boys that represent law and order (Ralph and Piggy), the boys have been drawn to Jack's band of hunters and their wild ways. Because he can supply their desire for meat and excitement, they forego a willingness to be organized, to work together, to create a lawful society like the one they were part of before coming to the island.