The swimmers are the collective protagonists and narrators of Parts 1 and 2. The number of swimmers in this group is undefined. Throughout their narrative, many first names are revealed but never in connection to a fully delineated person. Their traits, circumstances, and habits are all mixed together and revealed in lists that examine some aspect of the community as a whole rather than any individual.

Writing from the perspective of the entire group rather than a single character or an omniscient, third-person narrator allows the author to paint a bigger picture while maintaining a feeling of intimacy for readers as if they’re learning the swimmers’ secrets first-hand. The aspect of omniscience is present within the group, but their subjective views of non-swimmers—land people—support Julie Otsuka’s study of in-group culture.

In their lives outside the pool, the swimmers have varied professions, families, cultures, and personalities. Their devotion to swimming laps at the local pool unites them. More casual pool patrons may occupy the water at the same time, but they aren’t part of the community and so are practically invisible to the swimmers.