The Walrus is portrayed as an intelligent, but lazy conman, with the Carpenter as a dimwitted sidekick who needs beating with a cane for acting before thinking. After the Carpenter discovers a family of oysters underwater, the Walrus tries to persuade them to come "walk" with them. The Mother Oyster, on the other hand, knows that the current month is March, one of the 8 months with the letter "R" in which oysters are eaten. She tries to convince her children to stay in the sea, but the Walrus shuts her up (literally) and leads the dozen curious, younger oysters in a Pied Piper-like dance and flute solo ashore, where the Carpenter builds a restaurant from a shipwreck on the beach in six seconds. Once everyone is inside, the Walrus tricks him into preparing some food so that he can eat all the oysters himself. When the Carpenter returns to find every last oyster devoured and that the Walrus has double-crossed him, his face turns red with anger and he chases the Walrus outside with his hammer.

Walking upon a beach one night when both sun and moon are visible, the Walrus and Carpenter come upon an offshore bed of oysters, four of whom they invite to join them. To the disapproval of the eldest oyster, many more follow them. After walking along the beach (a point is made of the fact that the oysters are all neatly shod despite having no feet), the two main characters are revealed to be predatory and eat all of the oysters. After hearing the poem, the good-natured Alice attempts to determine which of the two leading characters might be the more sympathetic, but is thwarted by the twins' further interpretation: "I like the Walrus best," said Alice, "because you see he was a little sorry for the poor oysters."