The Queen's granddaughter, 33, embraced the summery weather in a tiered floral dress which she cinched in at the waist with a belt, and a matching pink hat.
WATCH: Princess Beatrice and royal family enjoy day one of Royal Ascot
The Duchess of Cornwall was also spotted making an arrival, looking lovely in an aquamarine coat dress by Anna Valentine and a hat by Philip Treacy, joining her husband Prince Charles for a day at the races.
Zara and Mike Tindall love a day at the races
The Countess of Wessex, dressed in pink, also made up the royal party, as did Mike and Zara Tindall.
Princess Beatrice and Edoardo Mapelli Mozzi attended day one of Royal Ascot
Members of the royal family typically step out in force for Royal Ascot although the Queen, who suffers from mobility issues and uses a walking stick, did not make an appearance at Tuesday's event.
She did, however, write a message in the official programme.
Prince Charles and Camilla rode in the first carriage in the procession
"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," she penned.
"Once again, it is thrilling that horses from around the globe have travelled to Royal Ascot to compete at the highest level."
The Kents and the Gloucesters shared one carriage
The Queen has more than ten horses entered over the five days of the event and, with her Windsor Castle home just a 15-minute drive away, there is still some hope that she will attend during the week.
The royals usually take part in a carriage procession around the racecourse at 2pm before the first race begins and Tuesday's opening day was no different.
Princess Anne rode in the third carriage
Charles and Camilla were joined in their carriage by Peter Phillips, while the Duke and Duchess of Gloucester and Prince and Princess Michael of Kent followed in the second carriage. Princess Anne rode in the third carriage with other notable guests.
Sophie Wessex enjoyed the day at the races
After the procession, the royals were able to enjoy proceedings from the Royal Enclosure and were pictured chatting and laughing.
Zara greeted Prince Charles with a hug after the carriage procession
Zara greeted her uncle Prince Charles with a warm hug, and was also seen catching up with her cousin Beatrice.
Over the course of the week, other members of the royal family are expected to make an appearance at the races. The Duke and Duchess of Cambridge usually attend once, with Kate even bringing her mother Carole Middleton one year.
Princess Beatrice and Zara Tindall enjoyed catching up together
Royal Ascot runs from 14 to 18 June and promises another spell of unparalleled racing from some of the industry's finest horses. It is also a change for spectators to don their finest and show off their sartorial elegance and magnificent millinery creations, often taking the lead from the royal family.
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