Charles, Camilla and other royals enjoyed a carriage ride past packed stands at the famous Berkshire racecourse which has not been filled since 2019.
Zara Tindall was spotted joking and laughing with her uncle Charles and at one point put her arm around the future king as they chatted.
The Queen was missing from the sporting event she is passionate about but is likely to have watched proceedings on television from Windsor Castle and been kept abreast of developments by her racing advisor John Warren.
The head of state has more than 10 horses entered over the five days of the event and, with her Berkshire home just a 15-minute drive away, there is still some hope she will attend during the week.
Writing in the official Royal Ascot programme, the Queen described the prospect of the world’s premiere thoroughbreds competing in Berkshire as “thrilling”.
She said: “After the challenges of recent times, this year’s royal meeting provides a long-awaited opportunity for supporters of racing from all over the world to come together for five days of outstanding sport.
“Once again, it is thrilling that horses from around the globe have travelled to Royal Ascot to compete at the highest level.”
The Queen’s horse Reach For The Moon, which missed out on being entered for the Epsom Derby, is favourite with some bookies to win the Hampton Court Stakes on Thursday with jockey Frankie Dettori taking the reins.
The Royal Family were out in force for their day at the races with Charles and Camilla joined by the Countess of Wessex, the Princess Royal and her children Peter Phillips and Zara, with her husband former England rugby star Mike Tindall.
Princess Beatrice and her husband Edoardo Mapelli Mozzi walked through the gates to the course with the other punters and were surrounded by photographers before making their way into an exclusive area.
As if to calm the frantic activity of the press, she said: “I’ll be here all day.”
The royal party mingled in the parade ring before racing began and Charles was spotted kissing his relatives and catching up with guests including Beatrice’s husband.
Other racegoers photographed among the crowds included the Duchess of Cambridge’s parents Carole and Michael Middleton.
Later in the royal box, Charles and Camilla stood clutching official programmes as they watched the racing from a balcony with Sophie, and they both looked through binoculars as they followed the horses around the course.
Royal Ascot is as much a social occasion as a sporting event with racegoers wearing summer dresses and flamboyant hats, as well as top hats and tails.
Milliner Viv Jenner was wearing an outlandish wide-brimmed hat she had created, and was happy to see the stands filled after last year when numbers were limited to 12,000-a-day as part of the Government’s Events Research Programme.
Royal Ascot is world-famous for the racing on display
David Davies
She said: “It’s amazing to have people back and not having the social distancing – it’s great to see. And it’s buzzing here and I’m loving it.
“It’s been empty the past few years, now finally Ascot is back to life.”
Sisters Anastasia and Maria Tutus wore colourful hats in honour of their mother’s homeland, Ukraine.
Anastasia, 19, from Ascot, said: “We’re both wearing modernised versions of traditional Ukrainian headdresses. We wanted to show we can celebrate Ukraine despite all that is happening in the country.”
Prince Charles and Camilla
David Davies
Prince Charles and Camilla at Royal Ascot
David Davies