The ringed female KL and an unringed male returned to Bassenthwaite at Easter and produced a trio of eggs in six days, the Lake District Osprey Project said.
Jon Carter from the project said staff were "delighted" the pair had bred again at the site.
Nearly 30 chicks have been raised at the nest since 2001.
Ospreys returned to the area after an absence of more than 150 years.
More than 1.5m people have visited viewpoints to see the birds of prey hunting over the lake.
A pair of ospreys which have returned to a nest in Cumbria for the fourth year running have produced three eggs.