The Katori-class cruisers were originally ordered to serve as training ships in the 1937 and 1939 Supplementary Naval Budget. With the Pacific War, they were used as administrative flagships for various fleets, such as submarine command and control and to command escort squadrons. The ships were upgraded as the war progressed with additional anti-aircraft guns and depth charges.
Kashima was completed at the Mitsubishi Yokohama shipyards on 31 May 1940 and was initially based at Kure Naval Base in the Inland Sea.
On 28 July 1940, Kashima and its sister ship participated in the last pre-war midshipman cruise visiting Etajima, Ominato, Dairen, Port Arthur and Shanghai. Soon after its return to Japan, Kashima was reassigned to the Japanese Fourth Fleet as flagship for CruDiv 18. On 1 December 1941, Kashima became flagship for Vice Admiral Shigeyoshi Inoue's Fourth Fleet based at Truk in the Caroline Islands. At the time of the Pearl Harbor attack, Kashima was at Truk.
During "Operation R" (the invasions of Rabaul and Kavieng), which took place from 23–24 January 1942, Kashima sortied from Truk to cover the landings of Japanese troops. Kashima later (20 February 1942) sortied from Truk in an unsuccessful pursuit of the aircraft carrier and American Task Force 11.
On 4 May 1942, during "Operation MO" (the invasions of Tulagi and Port Moresby), Kashima arrived at Rabaul, New Britain to direct operations, and was thus absent at the Battle of the Coral Sea, which occurred around the same time. After the successful landings of Japanese forces on New Guinea, Kashima returned to its base at Truk.
In July 1942, Kashima returned briefly to Kure for upgrading with two twin Type 96 25 mm AA guns, which were fitted in the forward part of the bridge. It then returned to Truk on 3 September 1942, where it continued to be based.
On 8 October 1942, a conference was held aboard Kashima to discuss the construction of defenses in the Pacific. The conference was attended by Rear Admiral Matome Ugaki Chief of Staff, Combined Fleet, and Imperial Japanese Army officials of the Defense Construction Department.
Later that month, on 26 October 1942 Vice Admiral Baron Tomoshige Samejima assumed command of the Fourth Fleet. He was replaced on 1 April 1943 by Vice Admiral Masami Kobayashi. During this time, Kashima was assigned to guard duty at Truk, with an occasional cruise around the Marshall Islands, or occasional return to Kure or Yokosuka for maintenance.
On 1 November 1943, Kashima was relieved as flagship of the Fourth Fleet by the light cruiser and was reassigned back to the Kure Training Division. On 18 November 1943, Kashima departed Truk with the submarine tender escorted by destroyers and . Shortly after departing Truk, the group was attacked by the submarine, which the Kashima group managed to sink without Japanese casualties. Kashima arrived at Kure on 25 November 1943, and was in dry-dock until 12 January 1944.
From 23 January - 15 April 1944, Kashima resumed its original role as a training ship for the Imperial Japanese Naval Academy at Etajima, and it made numerous cruises in the Inland Sea.
However, as the war situation continued to deteriorate for Japan, Kashima was pressed into service as a transport. From 26 May 1944 to 11 July 1944, it made four runs from Shimonoseki to Okinawa carrying army reinforcements and supplies. Likewise, from 11 July 1944 in "Operation Ro-Go", Kashima was assigned to transport personnel and supplies to Taiwan, making numerous voyages from Kagoshima and Kure to Keelung.
On 20 October 1944, Kashima was spotted by the submarine, which closed to within 2000yd, but was unable to attack as its new Mark 18-1 electric torpedoes lacked the speed and range.
On 20 December 1944, Kashima was modified at Kure Naval Arsenal with its torpedo tubes replaced by two unshielded twin 40-caliber Type 89 127 mm HA-gun mounts, four triple-mount Type 96 25 mm AA guns, along with a Type 22 surface-search radar, hydrophones and sonar. Two Type 2 infra-red communication devices were also installed. Kashimas aft compartments were modified into concrete-protected magazines for up to 100 depth charges, with four depth charge throwers and two rails installed on the quarterdeck. In addition, eight Type 96 single mount 25 mm AA guns were added, bringing the total number to 38 barrels, and a Type 13 air-search radar was also installed.
From February 1945, Kashima was assigned to anti-submarine patrol duty in the South China Sea and off Korea. On 19 May 1945, Kashima collided with and sank the cargo ship Daishin Maru in Tsushima Strait. A gasoline tank in Kashimas port bow was damaged in the collision, causing a fire, but she managed to make it to Chinkai, Korea for repairs. Kashima continued its convoy escort and anti-submarine patrols off Korea until the end of the war.
Kashima was officially stricken from the Navy list on 5 October 1945.
After the war, the American authorities used Kashima as a repatriation transport. A deck house was constructed around her main mast, and the barrels of her guns were sawn off.
From 10 October 1945 – 12 November 1946 Kashima made a total of 12 voyages to New Guinea, the Solomon Islands, Marshall Islands, Singapore, French Indochina, Taiwan, Indonesia, Thailand and Hong Kong, transporting some 5,800 former Imperial Japanese Army troops and POWs back to Japan.
Between 15 November 1946 and 15 June 1947, Kashima was broken up for scrap at Nagasaki.