The unattributed ἀκύματος πορθμὸς γελᾷ, Aeschylus’ κυμάτων γέλασμα, Plato’s κῦμα ἐκγελῶν, Pseudo-Aristotle’s τὸ κῦμα ἐπιγελᾷ, and Strabo’s στόματα ἐπιγελῶντα imply images of waves as laughing, spanning centuries in the ancient Greek canon. A linguistically and physically consistent analysis clarifies prior uncertainties and flaws in their interpretation. The analogy with human laughter is at the heart of the ancient Greek vocabulary for wave motions; shoaling waves broke into figurative laughter. Our reanalysis reveals the wordplay preparing the third wave in Respublica 5, the Peripatetics’ study of the swell life cycle in Problemata 23, and an appropriate site description in Geographica 11.