Orange and T-Mobile customers are set to gain access to fast, uninterrupted 3G services in more places, for more of the time.
Through the new Smart Signal Sharing project, smartphone, tablet and dongle users will be able to utilise both Everything Everywhere networks.
This means that if a signal starts to fade in a particular location, consumers will automatically receive a stronger signal - should it be available - from the other network.
If no 3G coverage is available, all Orange and T-Mobile devices will seamlessly switch to 2G signal and then back on to 3G when either network comes into range.
Olaf Swantee, Chief Executive of Everything Everywhere, said Smart Signal Sharing marks the completion of the Orange and T-Mobile signal integration project.
"This provides our 27.5 million customers with the widest 2G and 3G coverage available in Britain today," he stated.
"The launch is yet another proofpoint to our commitment to provide our customers with the best network in the UK - now and in the future."
In November 2011, Everything Everywhere announced an investment of £1.5 billion into its dual networks.
This was followed by the rollout of HSPA+ technology - which offers download speeds up to 21Mb - or 3.5G, which now reaches 95 per cent of the UK population.
Everything Everywhere hopes to launch 4G mobile broadband services on a small scale by the end of the year, using its existing 1,800MHz spectrum.
Media regulator Ofcom is currently consulting on whether to allow the firm to launch next-generation services prior to its 4G spectrum auction, which is scheduled for late 2012.