Yarmouth Castle was used as a coastguard signalling station until 1901, and was utilised during both world wars albeit on a small scale

Yarmouth castle on the Isle of Wight, hidden in a corner at the edge of the town, and flanked on two sides by the sea, has almost become lost among the outbuildings of the George Hotel. Some 500 years early though it was a completely different story. The castle played an important role in offering the islanders protection against French raids.

After witnessing the sinking of his flagship ‘Mary Rose’, Henry VIII wasted little time in ordering the building of Yarmouth Castle as one in a line of the many fortifications along the south and east coasts to ward of further advances by the French.

Yarmouth castle was completed in 1547, using stone from two Hampshire monasteries that had been dissolved by the King. The castles design broke with tradition and was square in plan with a pointed 'arrow-head' bastion in the south-east corner which protected the vulnerable area on the landward side, and allowed raking fire down the length of a moat situated along the south and east flanks.

Today the castle appears cramped as a result of the many alterations carried out down through the ages. Originally you would gain access to the castle through a doorway in the east wall leading onto a central courtyard area. The castles guns would have been sited on ramparts above the courtyard's perimeter. The soldier’s billets and provisions were situated along the southern perimeter wall. The arrow-head bastion served as the kitchen and service areas.

During the late 16th and early part of the 17th century, the courtyard was filled with earth to create a level gun platform. To help support the extra weight of the gun, angular buttresses were built on the seaward side of the west and north walls. Other modifications of the time included a second storey extension with gabled roof to the 'arrow-head' bastion, and an enlargement of the Master Gunners House in the south-east corner. During 1632, further refurbishment was carried out on what is now referred to as the 'Long Room', which is located in the south-west corner of the castle.

Controlled by the islands Captain, Richard Worsley, Yarmouth’s original armament comprised three cannon and culverins, as well as twelve smaller guns. Over the next 50 years several additions were made outside of the main castle to assist with extra ordinance, including an earthen bulwark with bastions.

During the time of the English Civil War, those of any social standing on the Isle of Wight were exclusively Royalist. The then current captain of Yarmouth castle, Barnaby Burley had every intention of holding the castle on behalf of the King. However, armed with only a small garrison, Burley decided that discretion was the better part of valour and surrendered the castle to the parliamentarians, who remained until the Reformation in 1660. Ten years later the outer earthworks were removed, the moat was filled in, and a large house was constructed which later became the George hotel.

There seems to have been little or no further changes to the castles appearance until 1813, when modifications were made to the platform parapet, and gun rails were laid to mount the traversing platforms of four large naval guns. In 1869, the guns were dismantled and six years later the current garrison was withdrawn. Yarmouth Castle was then used as a coastguard signalling station until 1901, and was utilised during both world wars albeit on a small scale. In 1984 the castle came under the control of English Heritage.