The summery cover is shot by Mario Testino. (source)
Click here to view last year cover featuring Edie Campbell, here to view 2015 cover featuring Gisele Bundchen, here to view 2015 cover featuring Daria Werbowy, here to view 2013 cover featuring Cara Delevingne, here to view 2012 cover featuring Lana Del Rey, here for 2011 cover with Rosie Huntington-Whiteley, and here for 2010 cover with Alexa Chung.