Warrior was first commissioned into the Royal Navy on 1st August 1861 whilst still being fitted out on the River Thames. The Honourable Arthur Cochrane, the third son of Admiral Thomas Cochrane, tenth Earl of Dundonald, was her Captain.

As she was a new and innovative ship the next few months were spent establishing her performance in trials. This led to some minor modifications and, in June 1862, Warrior was ready for active service in the Channel Squadron, patrolling coastal waters and making voyages to Lisbon and Gibraltar.

Warrior was the focus of attention wherever she went and when she toured the British ports in 1863 as many as six thousand people a day came to marvel at this symbol of British Naval power.

No wonder, as she was the largest, fastest and most heavily armoured and most heavily armed warship in the world. Not for nothing was she described as "The Black Snake amongst the rabbits in the Channel".

Although not the first iron ship, nor the first to use both sail and steam, Warrior combined these and other technological developments together and presented the greatest advance in ship design for centuries. She kept the peace by deterring the enemy. All other warships were obsolete the day Warrior was launched.

Warrior kick-started a change in naval technology which went at a pace never seen before. When her first commission ended in November 1864 she spent two years in harbour before rejoining the Channel Squadron for another four years in 1867. To many on board it must have seemed that Warrior's career would go on forever.

Foreign navies soon copied Warrior's design. Ships were built with ever thicker armour and ever more powerful guns. Engines too became increasingly efficient and, with coaling stations, and later oil, being established in many ports throughout the world, sails soon became obsolete. In only ten years, Warrior, once at the peak of Victorian technology was herself overtaken by progress. She was no longer a fearsome deterrent.

In 1875 Warrior began life as a Coastguard and Reserve ship, taking the officers and men from HMS Royal Alfred. Having been in refit since 1871, Warrior's masts, rigging and decks had all been renewed, and a poop deck had been added at the stern as it had been intended to make her flagship of the Admiral commanding the Mediterranean squadron. This star role was not to be, however, and so she found herself moored at Portland harbour for the majority of the next six years, making a single extended voyage each summer in the company of the reserve squadron.

The years passed largely uneventfully, apart from the sinking of HMS Vanguard in 1875, but in May 1881 Warrior again lost out to the Hercules - the ship that had ended up as flagship in the Mediterranean - when Rear Admiral the Duke of Edinburgh hoisted his flag in the latter ship, forcing an exchange of crews with Warrior. This latest change saw Warrior stationed at Greenock, where she would spend the remainder of her career in the coastguard.

Warrior's sea-going service ended in May 1883, when during her routine pre-summer cruise refit it was discovered that her main and foremasts were rotten, and would need replacing. Time and money were against the ship, her place was taken by the armour-plated Shannon, and Warrior was relegated to rotten row.