Microsoft is currently testing out a mobile data app that allows Windows 10 devices to connect to various mobile operators to access mobile internet, even if they don't have a contract with the providers, which suggests that the computing giant is working on its own SIM cards.

The mobile data app has been spotted on Microsoft's Windows Store, available to download for free. According to the description on the Windows Store, the app will enable users to connect to a "trusted national mobile data network" using only their Microsoft account, and users can pay for a short-term mobile data plan from the Windows Store as long as they are in a location where mobile coverage is available, and they have a "Microsoft SIM card".

The description also mentions that Microsoft plans to roll out an international roaming service in the future, and that the app will offer a "secure, high-speed mobile connection" at any time, but only with Windows 10 devices.

Microsoft hasn't officially announced its plans, or responded to press requests. However, the information seems to indicate that Microsoft would like to become a mobile virtual network enabler (MVNE), especially since leading MVNE Transatel announced on 5 January that its SIM 901 solution has been retained by Microsoft to support an "upcoming paid cellular data service for Windows 10".

"We want to promote the adoption of cellular connectivity on Windows tablets and laptops to complement classic Wi-Fi connectivity and make it easier for consumers to connect to the internet, anywhere, anytime," Eric Lockard, corporate vice president at Microsoft said in a Transatel press release.

"The Transatel SIM 901 solution helps us reach this objective in multiple markets through a single interface. In just a few clicks, consumers will be able to easily buy pre-paid data plans on supported Windows 10 devices."

The SIM 901 solution is already used by Transatel in 38 countries to offer 3G and 4G-LTE connectivity to users via trusted local mobile networks, with plans to expand to 50 countries by the end of the first quarter in 2016.