Banville accepted the €10,000 prize at a special ceremony held in Dublin last night.
Also present were writers Brian Dillon, who won the Argosy Irish Non-Fiction Book of the Year prize for his autobiographical In The Dark Room, and Kate Thompson, who won the Dublin Airport Authority Children’s Book of the Year award, for The New Policeman.
The prizes were worth €7,500 to Dillon and €5,000 to Thompson, and both writers were present for the gala dinner in Dun Laoghaire Yacht Club, where the winners were announced.
The Sea centres on the story of Max Morden, a middle-aged man who retreats to the seaside village of his childhood after his wife dies of cancer.
In The Dark Room sees Dillon write about the real-life loss of his parents.
And Thompson’s The New Policeman is a magical children’s novel, with an enigmatic figure at the centre of its plot whose identity is secret and only revealed at the end.
Writers that were beaten to the prizes include John McGahern, Deirdre Madden and Fintan O’Toole.