She escorted troop convoys from northern Norway when the Germans began evacuating the area beginning in October.

Z34 was transferred to the Baltic with two of her sister ships at the beginning of 1945 and participated in the action of 28 January 1945 when they were intercepted off the Norwegian coast by a pair of British light cruisers.

[1] The Type 1936A (Mob) destroyers carried enough fuel oil to give a range of 2,239 nautical miles (4,147 km; 2,577 mi) at a speed of 19 knots (35 km/h; 22 mph).

The following month, she was one of the escorts for the battleship Scharnhorst during Operation Ostfront on 25 December, an attempt to intercept the British Convoy JW 55B that was bound for the Soviet Union.

All of the battleship's escorts were detached the following day to increase the likelihood of intercepting the convoy and thus did not participate in the ensuing Battle of North Cape.

Z34 was damaged during British airstrikes on 17 July and 29 August; her crew helped to put out a fire aboard the oil tanker SS C. A. Larsen during the latter attack.

Three days later they were intercepted by a squadron of British ships, including the light cruisers Diadem, and Mauritius off the Sognefjord.

Laying smoke as they withdrew, the faster destroyers were able to outpace the cruisers and take shelter in Aspofjord protected by German coastal artillery.

[12][11] A week later she escorted the heavy cruiser Admiral Scheer as the latter bombarded Soviet positions near Frauenburg in support of the 4th Army.

[12][15] In early April, the ship escorted the ocean liners Deutschland and Pretoria as they carried 17,000 refugees to Copenhagen, Denmark.

During a duel with a Soviet coastal artillery battery at Oxhöft, a 15 cm shell prematurely detonated in the barrel and destroyed the gun.

While returning to Hela after another escort mission, the ship was attacked by two Soviet motor torpedo boats on the night of 15/16 April.

While drifting the next day, Z34 was attacked by Soviet aircraft and an anti-aircraft rocket detonated on deck, killing eight crewmen and wounding fourteen.