The Danube Delta forms Europe's second-largest river delta and its largest reedbed, with pelican colonies at Roșca-Buhaiova, fishing-village stilted houses, and the Black Sea coast at Mamaia stretching south of Constanța.
Pelican colonies at peak nesting, Tulcea boat tours running, and the Delta's reed channels accessible without summer mosquito density.
Mamaia beach at peak with Romanian and Moldovan summer crowds, Constanța's Roman mosaic and the Delta's pelicans both at peak season activity.
Bird migration peak with millions of birds passing through the Delta, Mamaia quieting after summer, and the Tulcea fishing harbour at autumn calm.
Cold Delta winters with the channels icing over in cold years, Constanța's old town walkable in cool air, and the spring migration starting in late February-March.