NHS Blood and Transplant (NHSBT) said the waiting time for receiving a new kidney has dropped by 18%.
New figures, released to mark World Kidney Day (9 March), show that between 2004 and 2008, patients were waiting an average of 1,153 days before receiving their new organ. Meanwhile, between 2009 and 2013, the figure fell to 944 days.
But too many people are still dying while waiting on the list, experts warned.
Since the last World Kidney Day in March 2016, 411 patients died while waiting for an organ transplant - of these 256 people were waiting for a kidney, or a kidney and another organ.
There are currently around 5,200 people waiting for a kidney, or a kidney and another organ.
But NHSBT said that the number of people on the NHS Organ Donor Register has reached its highest ever figure - 23.53 million.
“We’re encouraged that the number of people becoming donors has helped reduce how long desperately ill people wait before they receive a kidney transplant,” said Sally Johnson, NHS Blood and Transplant’s director of organ donation and transplantation.
“However, there is a still a severe shortage of donated organs.
“Two and a half years is far too long to wait for a kidney and far too many people die without ever receiving the transplant they need.
“Organ donation saves lives and we urge people to join the NHS Organ Donor Register and talk to their families about their decision.”
NHSBT added that in 2015/16, there were 1,364 deceased donors from across the UK - the highest ever figure.
Mechanic and electrician Jamie Madden, 32, from Sandhurst in Berkshire, became a kidney donor after he died in June 2015.
The 32-year-old had been working on a friend’s car when the axle stand gave way and the car collapsed on him.
His wife Hannah, 35, said: “I was just faced with the shock of losing my husband, and my initial thought was ‘you are not touching him’.
“But my husband was incredibly giving. And after speaking to his mum and dad and after thinking about it, we decided to donate.”
After the donation, Hannah and her two children received letters telling them Jamie’s kidneys had been successfully transplanted.
“When I got the letter, I started crying,” Mrs Madden said.
“I was very proud because Jamie lives on in somebody else.”
To find out more about organ donation or how to sign up to the register, visit www.organdonation.nhs.uk.