Around 120 horses from the regiment are on summer exercise (Picture: PA).
Soldiers and horses from The King's Troop Royal Horse Artillery splashed in the sea as they took a break from ceremonial duties in London.
The unit, which stars in the new Downton Abbey movie, is the Queen's ceremonial saluting battery and fires gun salutes for state occasions and royal birthdays.
Its soldiers are trained to drive teams of six horses that pull six First World War '13-pounder state saluting guns, and its gunners are also trained as combat soldiers.
Around 120 horses and 150 personnel left their barracks in London for an annual training visit to the North Norfolk coast.
They are based at Bodney Camp during their two-week visit, which includes three days on the beach at Holkham.
While the work may look fun, it is designed to build trust between horse and rider.
The bonds formed while working with horses in the waves, with hooves sinking into the sand giving a sense of uncertainty, help the teams deal with unpredictable events during high-profile ceremonial duties back in London.
Friday is their final day on the beach at Holkham, but they will go on to further military training, navigation and showjumping before returning to Woolwich Barracks.