A typical Robinsonade – a genre of fiction inspired by Daniel Defoe's Robinson Crusoe – and one of the most popular of its type, the book first went on sale in late 1857 and has never been out of print.

In the early 20th century, the novel was considered a classic for primary school children in the UK, and in the United States it was a staple of high-school suggested reading lists.

Modern critics consider the book's worldview to be dated and imperialist, but although less popular today, The Coral Island was adapted into a four-part children's television drama broadcast by ITV in 2000.

[2] Ballantyne never visited the coral islands of the South Pacific, relying instead on the accounts of others that were then beginning to emerge in Britain, which he exaggerated for theatrical effect by including "plenty of gore and violence meant to titillate his juvenile readership".

[9] Edmond describes the novel as "a fruit cocktail of other writing about the Pacific",[10] adding that "by modern standards Ballantyne's plagiarism in The Coral Island is startling".

[16] According to professor and author John Rennie Short, Ballantyne had a "deep religious conviction", and felt it his duty to educate Victorian middle-class boys – his target audience – in "codes of honour, decency, and religiosity".

[18][b] Ballantyne received between £50 and £60,[20] equivalent to about £6500 as of 2017[update],[c] but when the novel's popularity became evident and the number of editions increased he tried unsuccessfully to buy back the copyright.

[25] Ballantyne had been reading books by Darwin and by his rival Alfred Russel Wallace;[12] in later publications he also acknowledged the naturalist Henry Ogg Forbes.

[26] The interest in evolutionary theory was reflected in much contemporary popular literature,[27] and social Darwinism was an important factor contributing to the world view of the Victorians and their empire building.

[28] The story is written as a first person narrative from the perspective of 15-year-old Ralph Rover, one of three boys shipwrecked on the coral reef of a large but uninhabited Polynesian island.

With the memory of my boyish feelings strong upon me, I present my book especially to boys, in the earnest hope that they may derive valuable information, much pleasure, great profit, and unbounded amusement from its pages.

"[29] The account starts briskly; only four pages are devoted to Ralph's early life and a further fourteen to his voyage to the Pacific Ocean on board the Arrow.

The boys attempt to take Avatea in a small boat to a nearby island the chief of which has been converted, but en route they are overtaken by one of Tararo's war canoes and taken prisoner.

[23][34] Susan Maher, professor of English, notes that, in comparison to Robinson Crusoe, such books generally replaced some of the original's romance with a "pedestrian realism", exemplified by works such as The Coral Island and Frederick Marryat's 1841 novel Masterman Ready, or the Wreck of the Pacific.

[35] Romance, with its attention to character development, was only restored to the genre of boys' fiction with Robert Louis Stevenson's Treasure Island argues literary critic Lisa Honaker.

The Coral Island, for all its adventure, is greatly occupied with the realism of domestic fiction (the domain of the realist novel); Ballantyne devotes about a third of the book to descriptions of the boys' living arrangements.

[36] As Ralph says in his preface: "If there is any boy or man who loves to be melancholy and morose, and who cannot enter with kindly sympathy into the regions of fun, let me seriously advise him to shut my book and put it away.

[37] To a modern reader, Ballantyne's books can seem overly concerned with accounts of flora and fauna,[38] an "ethnographic gloss" intended to suggest that their settings are real places offering adventures to those who can reach them.

[37] They can also seem "obtrusively pious",[38] but, according to John Rennie Short, the moral tone of Ballantyne's writing is compensated for by his ability to tell a "cracking good yarn in an accessible and well-fashioned prose style".

Forward they went in ruthless indifference, shouting as they went, while high above their voices rang the dying shrieks of those wretched creatures as, one after another, the ponderous canoe passed over them, burst the eyeballs from their sockets, and sent the life-blood gushing from their mouths.

[41] Modern critics view this aspect of the novel less benevolently; Jerry Phillips, in a 1995 article, sees in The Coral Island the "perfect realiz[ation]" of "the official discourse of 19th century Pacific imperialism", which he argues was "obsessed with the purity of God, Trade, and the Nation.

In an essay published in College English in 2001, Martine Dutheil states that The Coral Island can be thought of as epitomising a move away from "the confidence and optimism of the early Victorian proponents of British imperialism" toward "self-consciousness and anxiety about colonial domination".

[56] It was widely admired by its contemporary readers, although modern critics view the text as featuring "dated colonialist themes and arguably racist undertones".

[61][62] Although mostly neglected by modern scholars[26] and generally considered to be dated in many aspects, in 2006 it was voted one of the top twenty Scottish novels at the 15th International World Wide Web Conference.

At the end of the novel, for instance, one of the naval officers who rescues the children mentions the book, commenting on the hunt for one of their number, Ralph, as a "jolly good show.