Charles, accompanied by Queen Camilla, marked the anniversary quietly with private prayers and a moment of reflection at Crathie Kirk, the parish church near the Balmoral estate where the she worshipped.
The service was a deeply personal moment for Charles, who became sovereign when his mother peacefully died last year at Balmoral on September 8, aged 96, after reigning for 70 years.
The King, dressed in a red tartan kilt, and Queen Camilla, in a blue day dress and cardigan, made the short journey by car from the estate just before 10am to the church where monarchs have worshipped since Queen Victoria. They were joined by Lady Sarah Chatto and the Earl of Snowdon.
The late Queen was close to her sister Princess Margaret’s children, especially Lady Sarah. The earl was accompanied by his daughter Lady Margarita Armstrong-Jones, and Lady Sarah by her husband Daniel and children Samuel and Arthur.
A small group of Balmoral estate workers and members of the public, including some pupils from Crathie Primary School, gathered close to the church to pay their respects. After the 30-minute service, the King and Queen made their way to speak to well-wishers who had gathered nearby.
The Rev Kenneth Mackenzie, minister of Crathie Kirk, who officiated at the event, said: "It was a simple reflective time, a time where we were able to give thanks for the life of the late Queen and recognise the poignancy of this day for that family and this community, as well as the nation and Commonwealth.
"I think that those of us that did get to see the Queen in different situations, but particularly up here, felt it today, were reminded of the loss.
"But we were also glad, just as the family were able to gather here last year, some members of the family were able to be here.
"And wherever they might be, in their own homes or wherever, I'm glad that people will have the opportunity to reflect and give some thanks for the life of the Queen."
The Prince and Princess of Wales, who visited the Welsh cathedral of St Davids for a short, private service, paid a personal tribute to the late Queen, saying: “We all miss you.”
The message, written by William and Kate on X, formerly known as Twitter, read: “Today we remember the extraordinary life and legacy of Her Late Majesty Queen Elizabeth. We all miss you. W & C.”
In one notable momentat the service, the couple walked to a portrait of the prince's grandmother and the princess laid flowers in front of the image. They then stood in solemn silence.
Meanwhile, a member of the public photographed William's younger brother, Prince Harry, leaving St. George's Chapel at Windsor Castle, the queen's final resting place, where he remembered the late Queen on Friday.
It came after the King recorded a message and released a favourite photograph of his mother to mark the anniversary and his accession to the throne. Charles said he recalled with “great affection her long life, devoted service and all she meant to so many of us”.
He added: “I am deeply grateful, too, for the love and support that has been shown to my wife and myself during this year as we do our utmost to be of service to you all.”
The formal colour photograph chosen by the King was taken by Cecil Beaton and shows her aged 42 in 1968. She is standing sideways and smiling in her Garter robes and wearing the Grand Duchess Vladimir’s Tiara, made of 15 interlaced diamond circles.
Princess Eugenie also paid tribute to her grandmother. She wrote on Instagram: “Thinking of you today. Missing you so much but remembering what a life of service, love and dedication to everyone and to your family, who loved you so very much. Forever grateful to you. And always in my heart.”
It accompanied an image of a smiling Eugenie sat next to the late Queen on what appears to be a bench outside a cabin at Balmoral.
Former rugby star Mike Tindall, who is married to Elizabeth’s granddaughter Zara, shared: “Massive day in the sport I love but I can’t help but start the day thinking about this wonderful woman that we lost a year ago today.”
Prime Minister Rishi Sunak also paid tribute to her, saying: “With the perspective of a year, the scale of her late Majesty’s service only seems greater. Her devotion to the nations of the United Kingdom and the Commonwealth only seems deeper. And our gratitude for such an extraordinary life of duty and dedication only continues to grow.”
Mr Sunak said he treasured his memories of meeting the Queen and was struck by her “wisdom, by her incredible warmth and grace”, and also her “sharp wit”.
Former prime minister Liz Truss has spoken about her final encounter with her, describing how the “upbeat” and frail but “mentally alert” monarch told her they would be “meeting again soon”. The Queen had welcomed Ms Truss to her home in Aberdeenshire on September 6, 2022 to appoint her prime minister. Ms Truss told GB News: “She was very determined to do her duty, right to the end.”
Friends also took to social media to remember the late and beloved queen. Her senior dresser and confidante, Angela Kelly, posted a black and white image of the queen with the message: "I will never forget you. I will always love you. I miss you my friend."
Elizabeth died two days later and an emotional 11 days followed as the London Bridge plans swung into action, with a lying in state, vigils and a grand state funeral, all played out on a public stage. The King has been staying at his Birkhall residence and Balmoral in Aberdeenshire over the summer.
He is not expected to have time in his diary to see his son Harry, who attended the WellChild award ceremony in Fulham last night ahead of the start of the Invictus Games in Germany.
Soldiers and horses who took part in the state funeral procession and proclamation salutes for the new reign were returning for Accession Day gun anniversary salutes in the King’s honour today. Captain Amy Cooper was set to give the order to fire a 41-gun salute at midday in Hyde Park.
A 62-gun salute was being fired at the Tower of London by The Honourable Artillery Company. Bells were also being rung at Westminster Abbey in commemoration of the King’s accession.