After reaching the approaches to the fjord, "Emden" transferred 350 of the men to the R-boats to allow them to go ashore. The element of surprise was lost, however, and on entering the narrows in the fjord, "Blücher" was engaged and sunk by Norwegian coastal defenses at Oscarsborg Fortress in the Battle of Drøbak Sound. "Lützow" was also damaged before the Germans broke off the attack. After the loss of "Blücher", "Emden" and "Lützow" disembarked their troops further down the fjord so they could attack the coastal defenses from the rear. Once the ground troops had begun their attack, "Emden" and "Lützow" closed with the Oscarborg fortress at 15:55 and began providing covering fire. The Germans then negotiated surrender terms with the other Norwegian forces later on 9 April. "Emden" entered the port on the morning of 10 April, thereafter serving as a joint communications center to coordinate Kriegsmarine, Wehrmacht, and Luftwaffe operations. She was relieved of this duty on 24 April, though she remained in Oslo until 7 June. During this period, "Großadmiral" (Grand Admiral) Erich Raeder visited the ship on 17 May. "Emden" arrived back in Swinemünde on 8 June, where she resumed training duties.