The couple, who recently returned from a trip to Egypt, Saudi Arabia and India, were relaxing at the royal Balmoral estate in Scotland. They planned no public celebration.
The pair smiled and waved at a small group of well-wishers gathered outside the nearby Crathie Parish Church, where they attended a morning service.
The wedding had originally been scheduled for April 8, 2005, but was postponed a day so that Charles could attend the funeral of Pope John Paul II.
The couple married in a small civil ceremony in Windsor, ending years of gossip about a relationship that began when they were in their 20s, before Charles met and married Princess Diana.
After a service attended by their families, Archbishop of Canterbury Rowan Williams blessed the union in a religious service at Windsor Castle.
Camilla took the title Duchess of Cornwall rather than Princess of Wales, in deference to enduring public affection for Diana.