The sea has a dual connotation. On the one hand, being “down beside the sea” (Line 1) and on “the sandy shore” (Line 3) evokes pleasant, nostalgic childhood memories. The sound of the waves crashing against the shore in rhythmic pushes and pulls creates a calming effect, lulling the listener into a sense of serenity and safety.

On the other hand, the sea can be a great, destructive force. The sea is vast and mysterious; no one knows for certain all that exists beneath its surface. This dichotomy between the pleasant and the unpleasant notions evoked by the vast sea mirrors the themes Stevenson conveys in this poem. The contentment and innocence conveyed through the recollection of digging holes in the sand contrasts with the transitory nature of childhood itself.

As stated earlier, a spade is a type of shovel with a squared-off shape at the end. The spade the speaker uses “[t]o dig the sandy shore” (Line 3) is like any toy shovel that children would use to dig at the beach. The spade here is representative of childhood itself, of memory and nostalgia. Since the spade is also a tool, it could also possibly be representative of the speaker’s industriousness, of the effort and work they’ll have to put into “digging the holes” of life.