The interests and demands of Swift's religious and literary career, and his enduring attachment to English friends, ensured that he became an experienced, if reluctant, sea-traveller. During his lifetime, Swift crossed the Irish Sea on more than twenty occasions, which reflects not just his continuous preoccupation with English affairs, political and personal, but a remarkable and fearless energy. The journey could take as little as a day in fine weather, or as long as three days in stormy conditions, and was usually an endurance test for travellers, never a simple pleasure. It was an elemental experience, often a dangerous one, which must have reinforced Swift's sense of Ireland as an isolated outpost, an island much further away from Wales than the modern experience or imagination might understand.

In the summer of 1726, Swift sailed to England, carrying with him a manuscript copy of Gulliver's Travels, looking forward to a reunion with friends he had not seen for over ten years. He spent most of that summer with Alexander Pope, at the poet's house in Twickenham on the banks of the Thames, whose elaborate gardens exemplified the latest fashion in "picturesque" landscape. In one of his most elaborate pseudonymous hoaxes, Swift then masqueraded as one "Richard Sympson", cousin of a retired seaman, Lemuel Gulliver, who wished to see his relative's memoirs made available to a reading public who enjoyed tales of remote and exotic places. In a letter to the printer, Benjamin Motte, Sympson emphasised Gulliver's philanthropic motive in publishing the work, saying that "the Author intends the Profit for the use of Poor Seamen". Motte was impressed, and arranged for a speedy publication of this strange story about a ship's surgeon who had seen and experienced so many near-incredible places on the other side of the globe. Not wishing to allow his presence in London to suggest the probable authorship of the Travels, Swift returned to Ireland. No sooner had he arrived back home, than he wrote to Pope, remarking on the strange and fascinating alterations in the cultural landscape which he had observed on his ride north:

. . . you will find what a quick change I made in seven days from London to the Deanery, through many nations and languages unknown to the civilized world. And I have often reflected in how few hours, with a swift horse or a strong gale, a man may come among a people as unknown to him as the Antipodes. His imagination full of the unsettling experience of Gulliver, it is as if the author now sees how, even in early eighteenth century Britain, a similar journey can take place, where the traveller seems to go back in time by rushing forward through space. Once across the Welsh border, the familiar and reassuring culture of Twickenham and Windsor must have seemed like another world, a dream-like era. The charade which Swift had played with Benjamin Motte backfired badly when it was discovered that the first printed edition of Gulliver's Travels, which was published in October 1726, was disfigured by many printing errors. Swift now decided, reluctantly, that he would have to return to London to arrange for an improved, second edition. In April 1727, he set sail from Ireland to oversee negotiations with the printer. This was to be his final voyage to England.