Continuing until June 27, the fair has two entrances, the traditional access point off Brompton Road and another through a tunnel opposite Kensington Olympia tube station which features a pattern of labelled paint swatches.
Doors opened to the public at 10:30 and the queues that had formed outside hurried in to explore the varied stock.
In addition to the usual supply of antiques and fine art, visitors will have access to the interiors and lifestyle offerings included elsewhere in the House & Garden Festival. It includes the events HOUSE, Spirit of Summer and GROW London.
This is the 46th staging of the event and is under the direction of Mary Claire Boyd of Clarion Events.
An extensive programme of talks includes Adrienne Chinn discussing styling with antiques, Eliska Sapera on mixing Middle Eastern furniture and artefacts with contemporary and English antiques and Vanessa Curry on collecting art.
Among the dealers participating this year are Babbington Fine Art, John Barkes, Joost van den Bergh, Patrick Sandberg and Boccara Design.