The Fiji class were designed within the restrictions of the London Naval Treaty of 1937. The 6" gun was selected over the weaker 5.25" gun because of newer Japanese cruiser designs.
More welding was used during the construction of the Fiji class cruisers.
There was one catapult to launch the three aircraft that were carried. There were two box hangers installed on either side of the front funnel. Originally the Walrus was carried and these were later replaced by the Sea Otter.
As the war progressed it was found that it was advisable to increase the anti-aircraft armament of the ships. Three of the ships, Ceylon, Newfoundland, and Uganda had there X turret replaced by two 4" twin mounts.