The Queen has pulled out of the Epsom Derby and will instead watch it on TV from Windsor, Buckingham Palace said.
The third day of the celebrations will also see tributes from the Prince of Wales and Duke of Cambridge at an open-air concert on Saturday evening.
William will also visit Cardiff, while Prince Edward is in Northern Ireland.
The Queen has been experiencing mobility problems in recent months and the palace had warned in advance that the monarch would consider which Jubilee events she felt able to attend.
The 96-year-old earlier pulled out of Friday’s Jubilee thanksgiving service after experiencing “discomfort” during Thursday’s events.
She had been due to attend Saturday’s iconic horse race, but her daughter, the Princess Royal, is expected to officially represent the monarch instead
Meanwhile, the Duke and Duchess of Cambridge are heading to Cardiff to meet the performers and crew behind a Jubilee concert at Cardiff Castle, which is separate to Saturday evening’s concert in London.
At the same time, the Earl and Countess of Wessex will carry out two engagements in Northern Ireland. Prince Edward – the Queen’s youngest son – and his wife Sophie will meet children taking part in multicultural street performances, join in with art and craft sessions, and speak to people sharing their personal memories of meeting the Queen.