The event was hosted by hairdresser Richard John, who owns most of the arcade and has his hair and beauty business there.
Worthing mayor Cathy Glynn-Davies joined town crier Bob Smytherman and Worthing Veterans Association to launch the party, with guests including staff dressed as 1920s Flapper girls.
Mr Smytherman said: "Today, we celebrate 100 wonderful years of this beautiful Royal Arcade, a true gem right here in the heart of Worthing, as we step back in time to the roaring 20s with Charleston singing and dancing to bring the Arcade's glamorous past to life.
"A special thank you to Richard John for hosting today's celebration and, more importantly, looking after and investing in the Royal Arcade all these years. I'm honoured to have worked in this arcade for some of those years. Here's to the next century of local shopping, community spirit, and timeless charm."
The opening of 'Worthing's handsome new shopping centre' was celebrated in the Worthing Gazette on Wednesday, June 3, 1925. Named The Arcade, it was described as 'a marked advance in Worthing's commercial capabilities and possibilities'.
The development had been in progress since the autumn of 1923, though the site had been derelict for some time. The Arcade covered the site of the old Royal Hotel, which was destroyed by fire in 1901.
The Gazette reported: "The completion of the project will place us in possession of the handsome assemblage of shops which bears the collective name The Arcade.
"The Worthing Development Company Limited, for that is the official title of the directors of this important enterprise, have added to existing business facilities by the provision of 35 shops, 18 of which have a frontage to Marine Parade and South Street, whilst 17 are within the Arcade itself.
"Some of the most enterprising local traders, perceiving the possibilities of this new centre, have acquired accommodation there, and we do not doubt that the shops which are at present unlet will speedily secure business."
Richard started his hairdressing business by renting one room on the first floor of the Royal Arcade in 1974 – and he is now landlord to almost all the tenants.
He worked long days with one member of staff to do shampooing. When the tobacconist in the shop below moved out, Richard took up the lease on the property and bought the freehold a few years later.
Then the property next door came up for sale, so he bought that, too, and expanded again when the property next to that became available. Most recently, he opened his new beauty salon, knocking through the whole run of shops to create one huge Richard John unit.
The site of the Royal Arcade is believed to be where Worthing's first pub, the Sea House Inn, once stood. The original building dating back to the 1740s was washed away but it was rebuilt as The Sea House Hotel. After a visit from Queen Adelaide in 1849, it was renamed the Royal Sea House Hotel.

5. The Royal Arcade 100 years
The Arcade covered the site of the old Royal Hotel, which was destroyed by fire in 1901 Photo: Richard John

6. The Royal Arcade 100 years
The Royal Arcade has always had a timeless charm Photo: Elaine Hammond

7. The Royal Arcade 100 years
The opening of 'Worthing's handsome new shopping centre' was celebrated in the Worthing Gazette on Wednesday, June 3, 1925 Photo: Worthing Gazette

8. The Royal Arcade 100 years
The new development in the 1920s included 35 shops, 18 with a frontage to Marine Parade and South Street, and 17 within the Arcade itself Photo: Richard John


