Seasonal wetlands are selective, “isolated” habitats of interest to ecology, evolutionary biology, and conservation. Seasonal wetlands in warmer climates (e.g., subtropical, Mediterranean) have been especially vulnerable to alteration and removal by people, and likely vulnerable to changing hydrology with climate change. Recent large-scale evaluations of seasonal wetlands have focused within a continent. Here I attempt to compare and contrast seasonal wetlands across continents, starting with wetlands in the upper Everglades of the Florida peninsula (USA) and in Doñana (Spain). The two regions differ in geology, climate, and research histories, but share other important conditions (seasonal precipitation, flat terrain, agricultural land use, and numerous seasonal wetlands. Perhaps this comparison can lead to future collaborations and even expansion to include other regions.