Audience figures peaked at 6.21 million (a 52% share) when Daley and Peter Waterfield took their final dive in the Olympics Aquatic Centre at 3.45pm.
The entire diving final never dipped below 5 million after it kicked off at 3.15pm.
Daley and Waterfield ended up finishing fourth in Men's Synchronised 10m Platform final, just outside the medal positions.
Daley will return to the water later in the Games in the individual diving.
Earlier this week, Rebecca Adlington's bronze-winning performance in the pool grabbed 9.6 million for BBC One.
London 2012 Olympics so far - Photo Gallery:
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Watch the stars talking to Digital Spy about London 2012 below: