William is a 56-year-old socialist from the late 19th century who mysteriously travels to the 21st century. He poses as a visitor from a faraway place to hide his temporal origins while investigating the structure of this future society. He frequently compares his industrial era to the egalitarian world he encounters, experiencing both confusion over outdated concepts like money and pure joy at the beauty of his surroundings.

Dick is a genial waterman who serves as Guest's tour guide through 21st-century London and the Thames. He embodies the typical citizen of his time by treating everyone as a neighbor, finding joy in physical labor, and expressing a childlike curiosity. He makes people feel comfortable with gentle jokes and defers to the wisdom of his elders when asked complex historical questions.

Clara represents the typical woman of the 21st century, combining modesty with a blunt, honest communication style. She accompanies Guest and Dick on their journey up the Thames. Taking advantage of the era's freedom from private property and strict marital binding, she acts according to her own affections and values domesticity without artificial burdens.

Ellen is a young, vibrant woman with bright hair, gray eyes, and a sun-tanned appearance. She frequently dances, giggles, and openly expresses her deep love for life and nature. Despite her playful demeanor, she engages deeply in political and historical conversations, acting as a counterweight to her grandfather's negative nostalgia.

Known as "Old" Hammond or the "sage of Bloomsbury," this 105-year-old man retains a sharp memory and acts as the primary historian for the 21st century. He explains the transition from industrial capitalism to the present communist utopia, recounting the civil wars of the 1950s and detailing the societal mechanisms of his era to Guest.

Bob is a weaver and friend of Dick who resides at the Hammersmith guest house. In the spirit of the new society, weaving is only one of his many voluntary pursuits, which also include printing, composing, mathematics, and writing.

Boffin is a tall, handsome man who works as a dustman but enjoys dressing in luxurious clothing. He takes his name as a joke referencing a Dickens character and spends his time writing reactionary novels filled with local color.

Annie is a resident of the Hammersmith guest house who helps see the traveling party off and welcomes them back. She exemplifies the open affection of the era by greeting Guest with a friendly kiss when he emerges in the morning.

Known as a grumbler and a praiser of past times, this old man stands out in the utopian society due to his negative disposition. He reads 19th-century literature and argues that life without competition has become stagnant and less vibrant, providing a rare voice of dissent against the new socialist order.

Walter is an old friend of Dick's who lives further up the river. He is dealing with the emotional aftermath of a recent tragedy in his community, illustrating that isolated incidents of violent passion still occur even in their peaceful society.

Described by Guest as a country version of Hammond, Henry Morsom is a knowledgeable local who explains the shift in work dynamics after the civil war. He details how people learned to choose and enjoy their labor rather than avoiding it.