More than 5,000 branded and own label confectionery products will line the shelves in what will be the family-run chain's 17th depot, and its first in the south of London.
The opening would be "a massive help" to the area's army of independent retailers, Hancocks managing director Mark Weston said.
"We have been looking for a decent site in the Croydon area for some time and this location in Commerce Park is excellent. Right in the heart of it, we are close to Booker, Bestway, Eastenders, Dhamecha and Costco, just off the A23.
"However, this really is fresh turf for us and we will be working hard to get ourselves known in the locality during the run up to Christmas an excellent time of year for retailers to take a look at how Hancocks can help their confectionery business grow," he added.
The depot's opening on October 10 will be celebrated with a week-long programme of promotional activity.