The coat of arms symbolizes the first city of Porto Calvo.
The three shells represent the three historic villages of the state, present-day Porto Calvo, Marechal Deodoro, and Penedo.
The three fish represent the three main and largest lagoons of the then-town: Mundaú, Manguaba, and Jequiá, and also represent fishing. The green bouquets in the center of the flag depict sugarcane and cotton.