Aquatic Warbler, Acrocephalus paludicola, is a species of passerine bird in the warbler family found in grassland and wetland ecosystems. It is patchily distributed across the Central and Eastern Europe. This species breeds in large open lowland marsh habitats with low grassy vegetation (mostly sedge fen mires) with water mostly less than 10 cm deep. On migration, it favours coastal habitats with low stands of sedge and reed near open water (European Red List 2015).

Acrocephalus paludicola has a breeding population size of 3300-3400 calling males and a breeding range size of 6800 square kilometres in the EU27. The breeding population trend in the EU27 is Decreasing in the short term and Unknown in the long term.

The EU population status of Acrocephalus paludicola was assessed as Threatened, as the species meets one or more of the IUCN Red List criteria for threatened at the EU27 scale.