This resulted in the choice of the dual purpose (DP) 15.5 cm/60 3rd Year Type naval guns as the main battery in five triple turrets capable of 55° elevation.

[4] The class was designed from the start to be upgraded into heavy cruisers with the replacement of their main battery with 20 cm/50 3rd Year Type naval guns in twin turrets.

She was officially commissioned on 31 October 1937; however instead of entering active service, she immediately returned to dry dock for refit work to upgrade her main battery to the heavy cruiser format with 20 cm/50 3rd Year Type naval guns.

[3] These upgrades were completed on 30 September 1939, at which she was assigned to Kure Naval District as Cruiser Division 7 of the IJN 2nd Fleet with her sister ships Mogami, Mikuma and Kumano.

Suzuya, under the command of Captain Masatomi Kimura, was dispatched on 23 January 1941 as part of a show of force following the Battle of Ko Chang in the Franco-Thai War.

At the time of the attack on Pearl Harbor, Suzuya was assigned to cover the invasion of Malaya as part of Vice Admiral Jisaburo Ozawa's First Southern Expeditionary Fleet, providing close support for landings of Japanese troops at Singora, Pattani and Kota Bharu.

From her base at Cam Rahn Bay, she sortied with Kumano to cover landings of troops at Anambas, Endau, Palembang and Banka Island, Sabang on Sumatra and Java in the Netherlands East Indies from the end of December 1941 to the middle of March.

[3] Mikuma, Mogami and destroyer Amagiri detached and formed the "Southern Group", which hunted for merchant shipping in the Bay of Bengal, while Suzuya, Kumano, and Shiokaze covered the northern areas.

Chōkai, light cruiser Yura, aircraft carrier Ryūjō and destroyers Ayanami, Yūgiri, Asagiri formed a center group to reinforce northern or southern wings as necessary.

[3] On 5 June, Admiral Isoroku Yamamoto, CINC of the Combined Fleet ordered CruDiv 7 to shell Midway Island in preparation for a Japanese landing.

On 24 August 1942, CruDiv 7 joined Vice Admiral Chuichi Nagumo's Carrier Strike Force (Shōkaku, Zuikaku, Zuihō and Ryūjō) with cruiser Chikuma northeast of Guadalcanal.

Suzuya, cruisers Maya, Tenryū, Chōkai, Kinugasa and Isuzu and destroyers Kazagumo, Makigumo, Michishio, Yūgumo, Asashio and Arashio bombarded the air strip with 989 203 mm (8 in) shells.

Kinugasa was sunk, Chōkai and Maya were damaged; Suzuya escaped unscathed, and through early January 1943 continued her patrols and coverage of transport convoys between Truk, Kavieng and Rabaul.

Suzuya departed Yokosuka on 16 June 1943, with another major resupply convoy to the Solomon Islands, and shuttled back and forth from Truk to Rabaul through the end of the year.

On 3 November, Suzuya with Mogami and Chikuma were dispatched from Rabaul to bombard American forces that just landed at Empress Augusta Bay, Bougainville Island, but the raid was prevented to reach gun range thanks to US Admiral Merill's victory, sinking the cruiser Sendai.

Suzuya was assigned to Admiral Kurita's "Force C" with the battleships Yamato, Musashi and aircraft carriers Zuihō, Chiyoda, Chitose, and cruisers Atago, Takao, Maya, Chōkai, Kumano, Chikuma, Tone, and Noshiro.

On 25 October 1944, in the Battle off Samar, Suzuya engaged the three "Jeep carriers" in American Task Group 77.4, but was attacked by ten TBM Avenger torpedo-bombers.