Captain Cat is a retired sea captain who lives in Llareggub. Late in life, he has lost his sight. Now blind, he has honed his listening skills to the point that he can identify different townspeople based on their idiosyncratic footsteps. Captain Cat’s ability to explore the town purely through his sense of hearing is important, especially as Under Milk Wood was originally written for the radio, a medium that relies entirely on sound. Therefore the audience’s sensory experience of Llareggub imitates Captain Cat’s lived experience, and he acts as the audience’s guide. Since life in Llareggub works in cycles and patterns, with people rarely changing their routine, the audience—guided by Captain Cat—can learn these predictable cycles and thus gain a better understanding of the town itself. Through careful listening, both Captain Cat and the audience can come to understand the town on a deeper level.

Captain Cat is significant because he is the only character who is permitted to take over the narration. First Voice and Second Voice cede the narration to the old captain, giving him the stage and allowing him to introduce the audience to a side of Llareggub that they cannot understand nearly as well as him.