Russia is the only country that borders both the Caspian Sea and the Black Sea. Its territory reaches the Caspian along the North Caucasus and the Black Sea along the western side of the Caucasus, giving Russia coastlines on two separate bodies of water.
The Caspian Sea is the world’s largest inland body of water, bordered by Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. The Black Sea is connected to the Mediterranean through the Bosporus, the Sea of Marmara and the Dardanelles. Russia’s Black Sea coast includes the important port city of Novorossiysk.
The answer is easy to mix up because Kazakhstan and Iran border the Caspian, while Turkey and Georgia border the Black Sea. None of those countries reaches both seas. Russia’s position between Eastern Europe and northern Asia also gives it borders with numerous countries, including China, Mongolia, Kazakhstan, Georgia and Azerbaijan.