The Amateur Swimming Association (ASA) has vowed to do all it can to reverse the decline in the number of people taking part in the sport.
Funding body Sport England announced a drop over the past year of 245,000 people - eight per cent - for swimming in its latest participation figures.
The body expressed its concern at the drop, which it says has skewed overall participation numbers in sport. Swimming now looks set for a funding cut, with a decision on that to be taken in March.
Giving his response to the Sport England figures, ASA chief executive Adam Paker said: "We are surprised to see such a fall in the number of those swimming regularly.
"There is now the opportunity for us to work towards a significant improvement and we are determined to seize this.
"We have already made a number of significant changes within our own organisation to ensure the ASA is fit to respond to these challenges, including a new programme of insight to help us attract new audiences and re-engage lapsed swimmers."
ASA group board chairman Edward Lord added: "We share Sport England's disappointment that their statistics point to a fall in the number of those swimming on a regular basis.
"There is clearly a major issue here and we will be putting all our resources into finding out both the cause of the fall in participation numbers and in identifying how we can move quickly with our partners to reverse that decline."
Great Britain's two-time Olympic champion swimmer Rebecca Adlington has described the figures as "worrying" and believes various factors are to blame for the decline.
Adlington told BBC Sport: "I think it is due to a number of different reasons.
"I think facilities are closing down and that people feel that even a lot of the ones that are up and running haven't necessarily had the love and 'TLC' they need.
"So people think 'hang on, I'm paying to swim when the facility isn't up to scratch' - there is the cost element to it.
"Also, I think it is one of those things that probably increases after Olympics.
"And in terms of the general profile, it is only on television once a year, which makes it very difficult to inspire young people and get people into it."
Sport England is also disappointed that tennis, basketball and golf continue to lose numbers.
Overall, there has been a 125,100 fall in participation in sport in England, according to the latest Active People's Survey - with swimming's figures wiping out the increase experienced in other sports including athletics as well as team sports such as football, rugby union, netball and cricket.
In the year ending October 2014, 125,100 fewer people did some kind of sport once a week for 30 minutes - bringing the overall number down from 15.7million to 15.6million.
Swimming is still the country's most popular sport with more than 2.6million people taking part weekly despite the drop. While the verdict on funding cuts for that and basketball will arrive in the coming weeks, tennis will not have restrictions after satisfying Sport England of its plans.
Sports minister Helen Grant said: ''I am very concerned by the overall dip in participation over the last 12 months. Sports governing bodies have long argued that they can bring new people to their sport and funding should go via them but some are simply not delivering and it's not good enough.''
Other sports on the up include canoeing, mountaineering, taekwondo and fencing, and Grant said governing bodies who had not increased participation now stood to lose some funding.
She added: ''I expect Sport England to take tough decisions and redirect funds from governing bodies that are failing to projects and organisations that will deliver.
''We may also need to look at setting bespoke targets so that sports up their efforts in getting more women, BME people and those from a lower social economic background into sport.
''Sports governing bodies should be left in no doubt that public funding to them is a privilege, not a right.''
Sport England's chief executive Jennie Price said swimming had failed to modernise and embrace the digital age, and had focused too much on its clubs rather than the whole population.
She said: ''A lot of other sports are very modern but when you got to a swimming pool there is probably not a digital device in sight.
''They have focused too much on clubs - only three per cent swim in a club and they have to concentrate on the other 97 per cent."