Motifs are recurring structures, contrasts, and literary devices that can help to develop and inform the text's major themes.

Work

The characters in On the Beach find salvation in work rather than religion. As in many of Shute's novels, the characters are always at work, and in this case, working until the last day of humanity. At first, it seems shocking that Peter would leave his wife and daughter to work when radiation sickness will soon end their lives. But Peter has not yet accepted the fact he will die: he is still planning for his future career, and he knows his wife has the same outlook. Furthermore, he really loves his work. Like many of the characters in this book, Peter would like to spend his last days working. Work is both a salvation and a distraction from thinking about the hopeless times in which they live. Because she does not have work to keep her busy, Moira spends her day drinking. When Dwight suggests to her that the time left might be a "period of grace," he is foreshadowing Moira's transformation into a sober and gentle woman who finds dignity in work during the last months of her life. The novel also shows other people working and taking pride in their work until the very end. During his last trip to Melbourne, Peter takes a ride on a tram driven by a man who says he will continue to drive it until he dies.

Sanity

The extreme events in the novel shift the characters' definitions of sanity, as nearly all the characters show a resistance to believing and accepting the situation. Dwight, for instance, though a practical man, still believes his family is alive and waiting for him in Connecticut. Delusion has become a practical means to cope with the enormous tragedy of the situation. Throughout the novel, characters continue going about their daily routines, doing their best to let ordinary activities fill their time and thoughts. In these surreal times, however, the more fervently people pursue these mundane activities, the more insane they appear. Peter and Mary's obsession with planning their garden years down the road, for instance, appears ridiculous. John, with his racing, and Douglas, with his vintage wine, are the only two characters who seem to take advantage of these last few days to live out their dreams and break with convention. Perhaps this is because, out of all the characters, these two men are have among the most realistic views of the situation they are in.

Obedience

On the Beach illustrates the danger of choosing obedience over morality and common sense. Shute implies that people do their jobs without thinking deeply about why they are doing them. Many who are in the government are trained to follow orders—not question them—and that is exactly what they do. For example, Peter fought in the war for a little while even though he did not know why he was fighting. Mindless obedience in the military, especially among its leadership, appears to be one of the primary reasons the war got out of control. Dwight admits he too would have behaved like the rest of the junior officers who were left in control, using every last bomb—he was trained to be obedient, not diplomatic and critically thinking. He would have defended his national honor without thinking of the moral consequences of his actions. Indeed, even in his final day, Dwight refuses to break the Navy rules. His need for obedience and order in his life is greater than his sense of obligation to comfort from Moira in his dying moments, so he prevents her from accompanying him onboard for the submarine's final voyage.

Like Dwight, Allan Sykes, the director of Fishing and Gaming, has a hard time breaking the rules he has obeyed for so long. Even though the circumstances are extreme, he has difficulty bringing himself to open the fishing season early. Because he is a government official, his attitude and behavior can be compared to those statesmen who participated in the nuclear war. These leaders had the choice between obedience and moral bravery and common sense; Shute implies that people will often choose obedience.