Earlier, on Saturday, the duke is expected to play in a charity polo match at the Santa Barbara Polo Club to benefit the American Friends of the Foundation of Prince William and Prince Harry, while the duchess gives out the prizes.
This is probably the best opportunity for the general public to get a glimpse of the couple, since most other events on their schedule are private, invitation-only affairs.
But the Polo Club will cost you: $400 tickets for a spot in the stands and $4,000 for V.I.P. seats, which include a private lunch created by Food Network chef Giada De Laurentiis.
The menu includes sweet corn lasagna with blistered tomatoes, pea pesto and beef tenderloin crostini.
Day three begins with more philanthropic work, starting with an event to support Tusk USA, an organization that raises funds for African wildlife.
Then the duke and duchess are to visit Inner-City Arts, an L.A. program that helps disadvantaged and homeless children through art. (This engagement is of particular concern to the duchess -- the palace noted that she's "extremely interested in how the arts can help young people unlock their potential.")
On their final afternoon in the States, they are scheduled to attend an event for military veterans transitioning to civilian life and their families at Sony Pictures Studios, where they'll help put together care packages. The event, titled "Hiring our Heroes Los Angeles, is hosted by ServiceNation: Mission Serve.
Then it's back across the pond to Britain for a much-needed rest.
ABC News' Michael S. James contributed to this report.