He was described in a tribute by his family as “the light of the family … he was everything we could have asked for”.
They said: “We are devastated by his loss and we would ask for our privacy to be respected while we grieve.”
Danny Edwards, Sean’s headteacher at Cox Green School in Maidenhead, added: “As a school community, our thoughts and heart-felt condolences go to Sean’s family and friends, I’m sure that words cannot adequately express the shock and agony they must be experiencing.
“Sean was a kind-hearted pupil with a close friendship group and had worked tirelessly in his recent GCSE exams to achieve his very best.”
Thames Valley Police said officers were called at 11.45am on Monday.
Superintendent Michael Greenwood, the LPA Commander for Windsor and Maidenhead, said: “This is an absolute tragedy in which a young boy has died after getting into difficulty in the water of Bray Lake.
“The boy’s next of kin have been notified and are being offered support at this extremely difficult and traumatic time.
“My thoughts, and the thoughts of all of us at Thames Valley Police are with the boy’s family and his friends, and we would ask that their privacy is respected.”