The boat ran aground leaving Cadiz harbor in November 1936 and had to be escorted home for repairs by her sister ship Albatros.

The 2nd Destroyer Flotilla, Seeadler and the torpedo boat Luchs escorted the battleships Scharnhorst and Gneisenau and the heavy cruiser Admiral Hipper during the initial stages of the sortie on 18 February before patrolling the Skaggerak until the 20th.

[13] During the Invasion of Norway in April 1940, the boat was assigned to Group 4 under Kapitän zur See (Captain) Friedrich Rieve on the light cruiser Karlsruhe, tasked to capture Kristiansand.

With only his forward guns able to bear and his ships loaded with troops, Rieve ordered them to turn away and lay a smoke screen to cover their withdrawal at 05:45.

Most of their bombs fell outside the fortifications, but one blew up the western ammunition dump and another near the signal station, killing two men and cutting most external communication lines.

Encouraged by sight of the blast from the annumition dump and the numerous hits all over the island on which the fortress was built, Rieve ordered his ships to make another try at 05:55, this time at an angle so that all guns could bear.

Accuracy for both sides was better this time, but no German ship was damaged and only a couple of shells from Karlsruhe landed inside the fort, wounding several gunners.

The cruiser's fire was generally ineffective, with more shells landing in the city, so Rieve withdrew around 07:30 and requested additional air support.

They were reported at two cruisers and their approach from a different direction caused some observers to think that they were not German, especially since there had been a rumor earlier of British ships spotted in the Skaggerak.

This caused the Norwegians to think that they were being saved by Allied ships and their guns did not open fire so the Germans landed without resistance and occupied the defenses beginning around 10:45.

After the heavy cruiser Lützow had been crippled by a British submarine off the Danish coast on 11 April, Seeadler, Greif and Luchs, among other ships, arrived the following morning to render assistance.

[16] On 18 April, Seeadler and her sisters Möwe, Greif, and the torpedo boat Wolf escorted minelayers as they laid anti-submarine minefields in the Kattegat.

Now assigned to the 5th Flotilla, Seeadler and her sisters, Greif, Falke, and Kondor laid a minefield in the English Channel on 30 September – 1 October.

[17] Seeadler, the torpedo boat Iltis and the destroyer Z4 Richard Beitzen were the escorts for a minelaying mission at the northern entrance to the Channel on 23–24 January 1941.

They joined the escort force for Scharnhorst, Gneisenau and the heavy cruiser Prinz Eugen on 12 February 1942 off Cap Gris-Nez during the Channel Dash.