Sendai was the lead ship of the Sendai-class light cruisers which preceded the Nagara-class cruisers. 8 were planned, but 2 were discontinued and 3 were cancelled due to the implementation of the Washington Naval Treaty, the remaining budget for the Sendai-class including the 2 discontinued cruisers were used for the Furataka-class light cruisers. Sendai-class light cruisers were equipped with four funnels and had better locations of their boilers, they are designed with a flying platform and a hangar, but they didn't actually carried any aircraft until the catapult system was installed in 1929.
Sendai was launched on October 30, 1923 and was commissioned on April 28, 1924. She's armed with seven 5.5 inch naval guns, two 3 inch anti-aircraft guns, four 24 inch torpedo tubes, and carries 48 to 56 naval mines, her speed could run from 35.25 to 35.3 knots. She also carries one floatplane which can be launched from her aircraft catapult.
Upon completion, she's immediately assigned to patrol the Yangtze River, she played a pivotal role during the Battle of Shanghai, and assisted several troop landings on Southern China during the Second Sino-Japanese War.
She was assigned as the flagship of DesRon 3. She was present in the invasion of British Malaya which General Yamashita Tomoyuki boarded her during the invasion. The commenced bombing on Kota Bharu. Then they were attacked by seven Hudson Bombers from the Royal Australian Air Force (RAAF), that they lost one transport ship and two were damaged.
During another escort mission, Sendai assisted on sinking the an RNN Submarine O-20, her Kawanishi E7K floatplane which spotted and bombed the submarine, the submarine was sunk by destroyer Uranami afterwards. She resumed escorting more convoys en route to Malaya, she engaged the USN submarine USS Seadragon SS-194, she also participated on the Battle off Endau and along with the destroyers, Fubuki, Hatsuyuki, Shirayuki, Amagiri, and Yugiri, they engaged the Royal Navy destroyes, Thanet and Australian destroyer, Vampire. Sendai and Shirayuki return fire at the Allied destroyer, they sunk Thanet while Vampire escaped.
After the battle, she covered troops landings in Sumatra, and patrolled the Straight of Malacca to prevent any British or Dutch vessels escaping from Singapore. She escorted troop landings in Andaman Island. She returned to Sesabo afterwards for repairs.
Sendai was also present during the Battle of Midway as part of the main body of the Combined Fleet, the main body remained behind the 1st Striking Force which Sendai didn't engaged any American Force, she stayed at Kure Naval Arsenal.
The DesRon 3 was reassigned, Sendai was supposed to be deployed for several operations in Burma and assist raids in the Indian Ocean, but this was cancelled because of the American Landings in Guadalcanal. The DesRon 3 escorted troop transport during the Solomons Campaign, Sendai bombarded Tulagi and assisted the bombardment of Henderson Field. She's present on the first naval engagement in Guadalcanal which she didn't received direct actions, she also participated in the second naval engagement which she was attacked by the USN battleship USS Washington BB-56 but manage to escape.
While on Rabaul, Sendai was reassigned to the IJN 8th Fleet and remained patrolled around Rabaul. She returned to Sasebo for repairs and several modifications. While off Kolombangara, she was attacked by land-based TBF Avengers, then she was attacked by two B-25 Mitchell bombers, and another from B-24 Liberators which she somehow survived all attacks with no damage.
She participated on the Battle of Empress Augusta Bay, which their objective is to defend the reinforcement of Bougainville Island, they were intercepted by the USN Task Force 59 which consists of 4 light cruisers and 8 destroyers. During the battle, Shigure first spotted the approaching USN fleet, she fired eight torpedoes at the enemies and turned starboard, Sendai also turned starboard which Sendai and Shigure almost collided. Sendai was detected under radar by the light cruisers USS Cleveland CL-55, USS Colombia CL-56, USS Montpelier CL-57, and USS Denver CL-58, Sendai becomes the concentration of 6-inch gunfire from the four cruisers which set her on fire. Sendai remains afloat while Hatsukaze sunk after receiving gunfire from the USN destroyers, Sendai sunk afterwards at 04:30, Captain Shoji and 184 crewmen went down with her, while 236 crewmen were rescued by destroyers. 76 more of her survivors were rescued by the Japanese Submarine RO-104, which includes Admiral Ijuin.
Sendai sunk November 3, 1943 at Empress Augusta Bay.