For the Landing at Cape Helles on 25 April, Cornwallis was assigned to the 1st Squadron, and she was tasked with covering the southernmost landing sites, W Beach and V Beach, along with the battleship and the armoured cruiser , which was the flagship of Rear Admiral Rosslyn Wemyss, the 1st Squadron commander. Early on the morning of 25 April, the three ships moved into position, having taken on the men of the first three battalions to go ashore. After arriving in her bombardment location, Cornwallis transferred the soldiers to trawlers, which in turn transferred them to small boats to carry them ashore to V Beach. Wemyss instructed Cornwallis to shell the Ottoman defences until the men had landed, and then to support the landing ship . Cornwallis conducted a heavy bombardment of the heights above V Beach as the British troops battled their way off the beach. By 10:00, the British troops had secured a beachhead, so Cornwallis left to support River Clyde that had been beached under heavy fire at Sedd el Bahr, but by this time, the decision had been made to refrain from landing the men stranded aboard River Clyde until nightfall, owing to the stiff Ottoman resistance.
