The authors of the issue are designer Belén Ríos Falcón from Germany and Zagreb designer Dean Roksandić.
The nominal value of the stamp, printed in 65,000 copies, is €1.70. The issue is accompanied by a first-day cover (FDC).
Croatian Foreign Minister Gordan Grlić Radman said on this occasion that "Croatia and Germany are connected by close and friendly relations and developed cooperation in numerous areas. As partner countries within the EU, we are united by our commitment to preserving democratic values and ensuring a secure European future."
The Danube is a recognisable symbol of connection and strengthening awareness of the intertwined economic, social, and cultural ties, and it has inspired numerous works of art, he added.
The Danube also encourages joint action in environmental protection and the preservation of water and biodiversity across 14 countries under the EU Strategy for the Danube Region, which aims to promote economic, cultural, and social development for 115 million inhabitants of the region, the minister said.
In the context of Croatian-German cooperation within the Strategy, there are two priority areas: boosting the competitiveness of enterprise and developing economic clusters with the German federal state of Baden-Württemberg, and preserving biodiversity, landscapes, and the quality of air and soil with the Bavarian government.