[6] When the Second World War broke out Draug had, as had her sister ships Troll and Garm, been mothballed for a number of years as part of pre–war savings on the Norwegian military budget.

When the reactivation order came, it took well over a month for workers to find and repair all the cracks and leaks in the ship's steam boilers and make her seaworthy again.

[7] The small destroyers of the Draug class were not considered fit for potential combat operations and were only meant to perform escort and guard duties.

[4] The beginning of April 1940 saw Draug part of the 2nd Naval District's 1st destroyer division,[8] covering an area roughly the same as the Vestlandet and Trøndelag regions.

[9] As she was finishing her escort mission, Draug received orders from the Norwegian Naval Command to return at full speed to Haugesund and refuel her coal stores.

[13] After receiving this information, Captain Horve had several personal telephone conversation with Rear admiral Carsten Tank-Nielsen, the Commander of the 2nd Naval District,[14] who told him that he had ordered the navy's ships in Bergen to open fire at any and all foreign warships that might try to force their way into that port.

Soon after the conversation, a Royal Norwegian Navy Air Service M.F.11 patrol bomber seaplane landed in the harbour and its pilot reported that German ships, U-boats and aircraft were in the area and that the city of Stavanger had most likely been occupied.

As Horve knew that the Naval Command headquarters in Bergen had been captured by the German invaders, he assumed that the order was false, although it later turned out it was not.

When ordered to steer his ship towards Britain, the captain of Main refused, only yielding after the Norwegian warship fired several warning shots and threatened to torpedo him.

The bombs, aimed at Main, missed but the German captain immediately scuttled his vessel and ordered his crew to abandon ship.

After the German sailors had boarded and lowered their life boat Draug fired eight to ten rounds into the waterline of the scuttled merchantman to ensure that she would sink.

[17][20] Now carrying sixty-seven German sailors along as PoWs in addition to her own crew of seventy-two,[17] Draug sped away towards Sullom Voe in the Shetland Islands.

[19] After arriving in the United Kingdom, many members of Draug's crew were transferred to Royal Navy ships and would serve aboard them during the remainder of the Norwegian Campaign.

[23] Draug's second-in-command, Lieutenant Østervold served as a liaison officer aboard the British light cruiser HMS Manchester during the April–May 1940 Namsos landings in Mid-Norway.

[24] The Chief Engineer on board, Kapteinløytnant (Lieutenant) B. M. Frimannslund, was left in command of the ship with 10-20 technical staff remaining to do maintenance work.

[29] After the initial invasion scare had passed, Draug spent most of her time up until April 1942 escorting coastal convoys off the coast of Southern England.

In addition to her coastal duties, Draug also carried out more unconventional operations, such as towing Norwegian motor torpedo boats to and from the coast of southern Norway.

After the successful attack MTB 56 dodged shells from both the escorts and a coastal battery at Korsneset and met Draug the next morning to be towed back to Lerwick in Shetland.