The prestigious honour which puts them centre stage at the height of the London tourist season is in recognition of the 25th anniversary of the Corps which is being celebrated this year.
The men and women in 3 Regiment RLC will change the Queen's Guard daily with Guardsmen from the Foot Guards until the end of July and then on alternate days in August and September.
They trained for six weeks to learn the complex drill manoeuvres and tasks involved in this ancient but very public military ceremony.
The soldiers who normally are drivers, suppliers and communications specialists, or chefs for the British Army are among the most demographically diverse units serving today.
It's a world away from their regular duties behind the scenes, so finding themselves representing their cap badge and the Army not only front of house, but in front of the most famous house in Britain, Buckingham Palace, is an experience these soldiers will treasure all their lives.