Jerry wants to strike out on his own and join in with the other boys as proof that he is old enough to be safe without his mother.

When Jerry reaches the rocks, he notices that there is an "edge of white surf" and the shining movement of water over white sand. Beyond this is the deep blue of the ocean. He races into the water and swims in "the real sea." After he has gone some distance, he looks back for his mother to be sure she is still on the other beach. He swims back to the shore, where "all at once" he feels lonely. Then, Jerry sees the older boys, who strip off their clothes and run toward the big rocks. Jerry feels a strong desire to join this group of boys. "To be with them, of them, was a craving that filled his whole body." Accordingly, Jerry swims closer. Then, one of the boys smiles and waves. "It was enough" for Jerry. He eagerly swims over the rocks near them, and he smiles with "a desperate, nervous supplication." However, when Jerry maintains his smile and does not speak, the others realize that he is a foreigner. "They proceed to forget him" by returning to their diving.  However, when Jerry swims around to the rocks to "take his place," they do move for him to get into line. "He felt accepted and he dived, carefully, proud of himself" in his new independence.

After a while, one of the biggest boys dives deeply into the water and does not quickly emerge, as has been done before. Worried about this boy, Jerry lets out a shout of warning. However, the others look at him without concern and turn their heads back toward the water. After a while, the boy who has dived into the deep water finally appears. He spurts water and shouts in triumph. Suddenly, the others dive in, and Jerry sees their dark forms moving through the water. He soon becomes aware that they are passing through a tunnel in the rocks below. The ability to accomplish this feat now separates him from the others.

In his desire to be the equal of the older boys, Jerry begins to search underwater for the hole through which the boys have passed. When he dives down and tries to enter the hole, Jerry sees nothing at the other end. He realizes that this is a fairly long tunnel. "He knew he must find his way through that cave, or hole, or tunnel, and out the other side." In fact, he feels that "the whole of his life" and all that he will become depends upon his ability to do what the other boys have done. "He would do it if it killed him, he said defiantly to himself." It is very important to Jerry that he makes himself the equal of these older boys.

It is very important for Jerry to feel accepted by the boys on the beach because "They were big boys -- men to Jerry."  He is no longer at the "safe beach" (representative of childhood), but rather the "wild bay" (representative of adulthood, a play where he is unprotected by his mother).  He is beginning to acquire more independence from his mother, and he wants to become a man, to be seen as a man.  The narrator says,

[The boys] were of that coast, all of them burned smooth dark brown, and speaking a language he did not understand.  To be with them, of them, was a craving that filled his whole body.

The boys seems somewhat exotic to Jerry: they are older than he is, better swimmers, and they look and speak differently from him.  To be accepted by them would be a real triumph to a younger outsider.

He dived, and they watched him, and when he swam around to take his place, they made way for him.  He felt he was accepted, and he dived again, carefully, proud of himself.

He feels that their tacit acceptance of him confirms that he is, indeed, prepare to be their peer.  And this makes the realization that Jerry cannot accomplish what the boys can (swimming through the tunnel) that much more crushing for him.  Their physical ability to do something he can't do is a very real confirmation that he is not truly their peer, that he isn't yet ready to make a full transition to adulthood.