Argassi Beach is a narrow strip of sand and shingle running below the resort's tavernas and small hotels. It is not a wild Ionian postcard beach, but it is convenient, shallow, and easy to use without planning. Families like it because the water stays gentle close to shore.
Sunbeds occupy much of the best space in summer, and the road is never far away. Treat it as a practical swimming beach and a place for an easy afternoon rather than the reason to come to Zakynthos. For bigger sand and a more protected bay, head south toward Kalamaki.