The Champotón River is only about 57 km long, but it gives the town its setting and much of its history. Before modern roads, the river was the practical route inland; today it is more useful for views, fishing, birdlife, and the sense of being at a real Gulf river mouth.
You see it best from the malecón and bridges. If you arrange a boat outing, ask locally about conditions and wildlife rather than expecting a formal tour circuit.