Diana, Princess of Wales' Memorial Playground reopened last week after a month-long job, said the Royal Parks Foundation, which funded the work.
"The playground opened eight years ago and is used by more than 750,000 children a year," said membership and projects officer Eleanor Shakeshaft.
"That's quite a lot of traffic, even though existing kit was manufactured to a very high spec. We wanted to encourage more interaction from children, so bought more kit."
Additions funded by the Royal Parks Foundation included a play tunnel, wooden pergola, wobble bridge and timber fort.
Existing equipment that underwent a spring clean included the pirate ship, teepees and the mermaid's rock.
Kensington Gardens park manager Tom Jarvis said: "The playground has attracted almost seven million visitors since it opened in June 2000.
"We hope this new play equipment will ensure millions more children enjoy the playground for years to come."