Fraudsters Nana Boateng and Jose Dias have admitted swindling £46,000 from the "Boris bike" scheme.
The 26-year-olds admitted making dozens of bogus refund payments from the London cycle hire scheme and giving them to their friends.
Southwark Crown Court heard how the duo organised the scam while working for Serco, the company that organises the bike scheme.
The pair unlawfully arranged for refunds to be put into the accounts of seven friends between September and December 2010.
Boateng, of Kingsway, Enfield, north London, and Dias, of Chatsworth Road, Clapton, east London, admitted one count each of fraud by abuse of position.
The charge against them reads: "Between September 21 2010 and December 1 2010, you dishonestly, and intending thereby to make a gain for yourself, abused your position as an employee of Serco, where you were expected to safeguard the financial interests of Transport for London, by arranging for the payment of refunds relating to the Barclays Cycle Hire Scheme to which recipients were not lawfully entitled."
Former Serco employee Devina Joseph-Albert, 22, of Glyn Road, Clapton, also admitted one charge of money laundering.
At previous hearings, seven other co-conspirators all admitted to one charge of money laundering.
All defendants will be sentenced at the same court on May 11.Suggest a correction