Fry spent a short spell on loan with the Addicks at the end of last season but did not make an appearance.
Under the terms of Fry's deal West Ham can recall him at any point after the first 28 days.
The youngster, who can play left-back or centre-half, signed his first professional contract with the Hammers in June 2009.
He joined Gillingham on loan in October and went on to play 13 times before returning to Upton Park in January after a knee injury ruled him out for six weeks.
Source: BBC Sport
Source: BBC Sport