Karen Doyle (née Mitchell) pleaded guilty to a charge of fraud by abuse of position when she appeared at Luton Crown Court on Monday (October 1).
Doyle, of Grantham Avenue in Braintree, has been released on unconditional bail ahead of a sentencing hearing on October 22.
The offence carries a maximum crown court sentence of 10 years imprisonment.
Her offending took place over a seven-year period, court papers reveal, ending February 2018.
Doyle, who most recently held the role of Marella Cruises general manager (supplier management and ancillary revenue), left Tui in May after nearly nine years with the operator.
She previously served as Tui general manager commercial relations and general manager cruise (distribution).
A Tui spokesperson told TTG: “We take any fraudulent activity incredibly seriously and welcome today’s outcome.
"This is a clear warning to anyone considering anything similar and we will not hesitate to take legal action or refer such matters to the relevant authorities.”
Doyle previously held roles with Royal Caribbean International, Air UK, Emirates, Cunard and Thomas Cook.