During the Russo-Japanese War, Fölkersam was appointed commander of the 2nd battleship division of the 2nd Pacific Squadron, with the battleship as his flagship. The squadron departed the Baltic Sea on 15 October 1904 under the command of Admiral Zinovy Rozhestvensky on a voyage around the southern tip of Africa, across the Indian Ocean and north to the Tsushima Straits in an attempt to relieve the Japanese blockade of Port Arthur. Fölkersam was already seriously ill with cancer. Rozhestvensky was aware of Fölkersam's condition, and when the fleet reached Tangier, he assigned Fölkersahm to an independent command consisting of five older warships and several transports, which transited the Suez Canal and rejoined the main fleet at Nossi Be in Madagascar. However, Fölkersam was incapacitated from early April 1905. On 24 May 1905, shortly before reaching the Sea of Japan, he died. Rozhestvensky, concerned with the effect of Fölkersam's death on morale, ordered that the news be kept secret from the crew and the rest of the fleet. Fölkersam's body was placed in the cold store of the ship, and his flag was kept flying on the "Oslyabya". During the Battle of Tsushima three days later, "Oslyabya" was the first ship to be sunk by the Imperial Japanese Navy, and Fölkersam's body went down with his ship.