Under the deal BT will manage Ebookers' customer contact centre and its wide area network. The service will include management, maintenance and support for communications technologies across the contact centres.
The online retailer had previously held agreements with several suppliers, each with a different service level agreement and billing arrangements.
Ebookers is using the telecoms company to renegotiate contracts with each of its suppliers, which the telecoms giant will then consolidate into one contract with the travel agent.
Brent Spicer, business development director at Ebookers, said the renegotiation could save the company more than £1.6m over five years.
"We have managed to get some additional services such as an outsourced helpdesk to provide a single point of contact," he said.
According to Spicer, BT can easily add additional services to the existing system, which supports the growth targets of the business.
Dinesh Dhamija, founder and chief executive of Ebookers, said the increasing size of the internet business meant that "an efficient contact centre and robust reliable network is crucial to maintain a high standard of customer service."