The princess wore the jewellery designer's personalised gold Midnight Moon necklace (£1,100) and its fixed alphabet necklace, also in gold (£325).
The Midnight Moon was engraved with George, Charlotte and Louis's initials, while the alphabet necklace featured them as three individual charms.
William and Kate were cheered when they arrived on the island for a two-day visit, where they showed off their creative and DIY skills by helping to renovate Aros Hall, a community-owned space in the picturesque coastal town of Tobermory.
The couple married 14 years ago on April 29, 2011 and spent the night at a self-catering cottage on the island, which has a number of luxury accommodation sites.
William told Interior designer and Mull resident Banjo Beale and others: "It was 2003 when we were here. We had a lovely time here - it's wonderful."
He said that on their current visit to Scotland, they are "trying to find out what challenges there are, what we can do to help".
