British Swimming says it will carry out a thorough review following a "disappointing" Olympic campaign.
Rebecca Adlington won two bronze medals
Michael Jamieson a silver,
but that was short of UK Sport's target of between five and seven podium finishes.
British Swimming could now face a funding cut ahead of the 2016 Games.
Performance director Michael Scott said: "Following our disappointment at not meeting our high expectations we'll undertake a thorough debrief."
GB swim medals 2008 and 2012
gold x two (400m and 800m freestyle)
silver (10km marathon)
silver (10km marathon)
bronze (10km marathon)
bronze (400m freestyle)
silver (200m breaststroke)
bronze x two (400m and 800m freestyle)
Scott, who will lead the review, added: "In the Olympic cycle to London, the British swimming team has achieved best-ever results at World, Commonwealth and European level but in London we failed to continue this trend and we need to fully understand why."
The medal haul of three was half of that achieved by Team GB four years earlier.
Expectations had been raised after the team claimed six medals at the 2011 World Championships. But, while they managed 23 finalists in the Aquatics Centre pool, they were unable to convert two fourth and six fifth-placed finishes into medals - something which the review will scrutinise ahead of the new funds being allocated in December.
Swimming received a total of £25.1m ahead of London 2012 and was in the same funding bracket as cycling, rowing and sailing, which have all exceeded their medal expectations this summer.
One of the biggest disappointments for British Swimming was that the times delivered by its athletes did not always match expectations.
Other than Jamieson, few bettered the performances they delivered at the GB London 2012 trials in March, which was particularly surprising given other nations did not appear to share those struggles.
Adlington herself admitted that, at times, she found the home crowd "overwhelming".
Scott, who is contracted for the next Olympic cycle, added: "Britain had more finalists than ever before with 23 in the pool, but we were not able to convert the two fourth and six fifth places into medals and that is what we hope to better understand with the performance debrief.
"In order that we can continue to improve as a swimming nation, this will be done quickly but thoroughly with a view to completing by the end of October."