Customers with 3 will soon see adverts displayed in the mobile broadband software launch screen on their laptops.
The dashboard, which appears when a user inserts their 3G dongle into the PC, will now bear advertisers' messages alongside connection details.
Announcing the move, the internet service provider (ISP) said that it is actively seeking advertising partners to provide marketing content for its one million UK mobile broadband users.
In Austria, where 3 has already introduced advertising on its dashboard, major car manufacturers including Land Rover and Honda have been among the brands using the service.
Neil Andrews, Head of Advertising at the ISP's UK office, said: "3 UK has always led the market when it comes to providing innovative advertising space on mobile because we have a uniquely powerful network.
"This has allowed us to do some very interesting things with mobile content and the advertising surrounding us."
Last month, the mobile broadband operator was among the first to lower its data rates for laptop users roaming across the EU.