Sky Mobile will allow users to keep unused data for up to three years and use it whenever they choose to. Other "flexible" options include giving people the option to change their phone plan every month.
Customers signed up to the broadcaster’s TV service will receive free UK calls and texts, and "sync with their Sky+ box".
However, customers will need to sign up to a 12-month contract. The monthly price of the contracts will begin at £10.
Stephen van Rooyen, UK and Ireland chief executive at Sky, said: "We felt it was time to shake up the mobile market and give customers a completely new way to manage their mobile plan - something no one else is offering.
"We've designed it based on what people told us they want – it's easy, flexible and transparent and it puts the customer in control. With £2 billion being wasted each year on unused data in the UK, Sky Mobile customers will only pay for what they use.
"Plus we're giving Sky TV customers a fantastic offer which will allow them to get even more value from their subscriptions. It's time for people to have a smart new way to manage their mobile contract."