In early February 1904, the Japanese Navy launched a surprise attack on the Russian fleet at Port Arthur. "Sevastopol" was hit by one shell, either six or eight inches in diameter, that wounded two men on her bridge. She soon turned in pursuit along with other ships of the Russian fleet, all firing their forward guns, but she failed to score any hits. On 26 March 1904, "Sevastopol" was accidentally rammed by , damaging a propeller. After the attack on Port Arthur, the First Pacific Squadron tried to break out several times. During one attempt on 23 June, Admiral Wilgelm Vitgeft, commanding the Pacific Fleet, retreated after encountering the Japanese fleet. Approaching the harbor, "Sevastopol" moved slightly out of formation and hit a mine that killed 11 and caused severe flooding, but managed to get inside the harbor and drop anchor. She was under repair for six weeks, during which time a fire broke out on deck, killing 2 and wounding 28. The Russian battleships were too big to fit into the dry dock at Port Arthur, so large caissons were built to provide access to the ships' hulls. On 9 August, with the Japanese Third Army assaulting the outer defenses of Port Arthur, the First Pacific Squadron sortied from its base. Even though "Sevastopol" was not fully repaired, she sailed with the rest of the fleet with one gun in her aft turret remaining inoperable. They later engaged the Japanese fleet in what would become the Battle of the Yellow Sea.