The record figure has made the competition the biggest of its kind in the UK.
The 400 entries will be whittled down during almost a week of beer judging to 72 national finalists before the overall SIBA Champion Craft Keg Beer is named.
SIBA hosts the Independent Beer Awards, which will take place at the BeerAlive beer festival, part of SIBA's annual BeerX Trade Show next month (March) in Sheffield.
SIBA managing director Mike Benner said the craft keg beer boom shows the dexterity of Britain's independent brewers, who are producing quality beers in various styles and formats.
He added: "We have seen a huge growth in the number of independent craft brewers producing quality beer in a range of formats including the increasingly popular craft keg.
"Certain beers lend themselves to being served in this way and while cask will always be important for our members, it is great to see breweries embracing quality keg beer and producing fantastic tasting, unpasteurised beers that are served chilled, direct from regular keg fonts."
SIBA's competition started in 2011 with 50 beers being put forward nationally that first year.
By 2014 there were 208 entries nationwide and this increased further in 2015 when entries rose to 238.
Benner said: "In 2017 we are seeing British independent craft brewers producing amazing beer in a variety of formats, which allows venues such as restaurants and bars as well as coffee shops and hotels to meet customer demand for craft beer without having to invest in the training or technology needed to serve cask beer.
"As well as keg beer, which is somewhat easier to look after and can be connected directly to existing lager fonts, we are increasingly seeing brewers put their beer into 330ml bottles and cans, which are perfect for casual dining outlets or businesses looking to serve craft beer."
Last year (August) SIBA launched a new accreditation scheme to reclaim the word "craft" for truly independent brewers.
The brewing body said it would provide a "stamp of approval" for brewers that meet its size and capacity requirements to be considered independent and that pledged to abide by its Manual of Good Brewing Practice.