Millwall, Dover Athletic (loan), Grays Athletic, Ebbsfleet United, Boreham Wood (loan)
On 4 September 2007, Preston made his first professional appearance for Millwall when coming on as a sub against Swansea City in the Football League Trophy first round.
In January 2009, he joined Isthmian League Premier Division club Dover Athletic on loan after an injury to the club's first-choice goalkeeper, John Whitehouse. He made his debut in a 0-0 draw against local rivals Ramsgate. Whilst at Dover Athletic, he helped them secure the title and promotion to the Conference South. On 22 June 2009, he rejected a new one-year deal from Millwall, and was therefore out of contract and released.
At the start of the 2009-10 season, Edwards signed for Grays Athletic along with eight other players. On 24 March 2010, Edwards played in a behind closed doors reserve match for Crystal Palace against Millwall. He was released at the end of the 2009-10 season.
Edwards signed for Ebbsfleet United on 28 July 2010, after a successful trial period. In October 2010 Edwards was called up to the England C team for the first time. He became a YouTube sensation in February 2011, racking up over eight million views (as of late June 2014), after being sent off just ten seconds into a 3-0 defeat to Farnborough. This is believed to be a record for a goalkeeper. Despite this setback, Preston became a fan favourite amongst club fans and a key asset for the club. After promotion, Preston asserted himself as Ebbsfleet number one before an ankle injury cut his season short. Despite the club finishing second bottom of the Conference Premier in the 2012-13 season, Edwards drew praise from many for his performances throughout the season and went on to dominate the club's end of season awards ceremony, winning a large majority of the trophies on offer including the Players player of the year and the Fans player of the year award. Although it was rumoured that his services were wanted by John Still, the recently appointed manager of Luton Town, Edwards signed a new contract with the club, keeping him on for the 2013-14 season.
Edwards continued as the club's first-choice goalkeeper for the 2013-14 season and was kept on for the 2014-15 campaign. During that season, his spot as the club's first choice goalkeeper was challenged by Brandon Hall. Manager Jamie Day brought him back into the team for the FA Trophy clash with Forest Green Rovers on 10 January in which he helped secure a 1-0 win. Edwards made his 200th appearance for the club in the 2-2 draw with Hemel Hempstead Town in late February. He is seventh in the appearances list of Ebbsfleet goalkeepers down the years, standing alongside club legends including Brian Hughes and Lee Smelt.
Ahead of the 2015-16 season, Edwards joined newly promoted National League side Boreham Wood on a season-long loan deal. However, the deal was cut short with Edwards making only six league appearances, and he went on to join Isthmian League Premier Division side Dulwich Hamlet on the 20 February 2016 for the remainder of the season.