Deakin was Leader of the Opposition from April 1910 until ill-health forced his resignation on 20 January 1913. Joseph Cook replaced him as leader of the Liberal Party that Deakin had founded in 1909. Deakin retired from politics when the parliament was dissolved in May 1913 and Joseph Cook became Prime Minister after the general election on 31 May 1913.

Deakin participated little in public life after his retirement, though he and Pattie Deakin made an official trip to the International Exposition in San Francisco in February 1915, held to celebrate the opening of the Panama Canal. Suffering increasing ill-health, including a severe progressive memory loss that had first afflicted him in 1908, Deakin found his duties in San Francisco an ordeal.

The Deakins also travelled to London in 1916, returning via New York early in 1917. Deakin’s condition worsened and, in the notebook journals he had always kept, he wrote ‘My memory is but a little fiction’. In September 1919 he suffered a stroke and died on 7 October, aged 63.

Deakin was given a state funeral, his coffin brought from his house in Walsh Street, South Yarra to Parliament House. It was taken from there in a silent procession through the city streets. He was buried in the St Kilda cemetery next to the graves of his parents.

Pattie Deakin died 15 years later, on 30 December 1934. She was interred in her husband’s grave.