1930s
| Year | Date | Event |
| 1930 | 16 August | The first British Empire Games, the forerunners of the Commonwealth Games, open in Hamilton, Canada. |
| 1 October | 7th Imperial Conference convenes in London. Meeting drafts what becomes the Statute of Westminster. | |
| 1931 | 11 December | The Statute of Westminster 1931 is enacted, formalises the Balfour Declaration 1926, with the Parliament of the United Kingdom renouncing legislative power over the dominions. It is adopted by Canada, the Irish Free State, Newfoundland, and the Union of South Africa. Australia and New Zealand decline to adopt it. |
| 1932 | 21 July | The British Empire Economic Conference is convened. Policy of Imperial preference adopted. |
| 1934 | 16 February | The self-government of the Dominion of Newfoundland is suspended, replaced by the Commission of Government. Newfoundland ceases to be in the Commonwealth. |
| 4 August | The second British Empire Games open in London, the United Kingdom. | |
| 1936 | 20 January | King George V dies, being succeeded by Edward VIII. |
| 10 December | King Edward VIII signs the instruments of abdication, effective the next day. | |
| 11 December | The United Kingdom passes His Majesty's Declaration of Abdication Act 1936 (which, at the request of those countries' Parliaments, equally applies to Australia, New Zealand, and South Africa), effecting Edward VIII's abdication and succession by George VI. Canada passes the Succession to the Throne Act to the same effect. | |
| The Constitution (Amendment No. 27) Act 1936 of the Irish Free State comes into effect, removing reference to the King in the Constitution. | ||
| 12 December | The Irish Free State passes the Executive Authority (External Relations) Act 1936, resurrecting the office of king and recognising George VI as Edward VIII's successor, one day after the rest of the Commonwealth. | |
| 1937 | 14 May to 24 June | 8th and final Imperial Conference held in London following the coronation of King George VI; rejects concept of Imperial Federation. |
| 29 December | A new Irish constitution is promulgated, transforming the Irish Free State into 'Republic of Ireland', creating the position of President, and calling into question who the Irish Head of State was. | |
| 1938 | 5 February | The third British Empire Games open in Sydney, Australia. |
| 1939 | 1 September | Nazi Germany invades Poland, precipitating an ultimatum from the United Kingdom, which was ignored by Germany, leading inexorably to the Second World War. |
| 2 September | Irish Taoiseach Éamon de Valera announces his intention to remain neutral in the impending war, regardless of British policy. The government declares the Emergency. | |
| 3 September | The United Kingdom declares war upon Nazi Germany, beginning the British Empire and Commonwealth's involvement in the six-year conflict. | |
| Australia legally joins the Commonwealth, although this is only effected by the retroactive commencement of the Statute of Westminster Adoption Act 1942 three years later. | ||
| 4 September | South Africa's United Party refuses to accept Prime Minister Barry Hertzog's declaration of neutrality in the war, and vote to replace him as party leader with Jan Smuts. | |
| 6 September | South Africa declares war upon Nazi Germany, becoming the first dominion to do so independently of the United Kingdom. | |
| 9 September | Canada declares war upon Nazi Germany. |
Read more about this topic: Timeline Of Commonwealth Of Nations History