A group locked themselves together after storming the airport's single runway on Tuesday, apparently accessing the site via the River Thames.
Scotland Yard says nine people have been charged with aggravated trespass and being unlawfully airside within a restricted area of an aerodrome and will appear in court later this month.
Protesters occupied the runway shortly after 5.30am on Tuesday and the final two members of the group were arrested nearly six hours later. The runway was reopened at midday.
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The demonstration resulted in all flights in and out of the airport being cancelled, delayed or diverted.
The campaigners, whose international movement was set up following the killing of black teenager Trayvon Martin in Florida four years ago, said Tuesday's action was taken "in order to highlight the UK's environmental impact on the lives of black people locally and globally".
