All boats wishing to race and compete shall comply with the International 420 Class Rules. The current International 420 Class Rules are published on the ISAF website and you should always refer to the ISAF website to ensure you have the latest version. The 2013  International 420 Class Rules will come into effect on 1 January 2013.

In 2006, in addition to the documentation on the ISAF website, the 420 Class published a "Clarification to the 2006 Class Rules" to highlight the changes of major concern for sailors.

Archive Class Rule documents and interpretations are also available on the ISAF website.