It is one of the most consequential developments in telecoms infrastructure in a decade, and it is already live.

The basic concept

Mobile networks have always relied on ground-based infrastructure: towers, masts, and small cells. If you are out of range of that infrastructure, you lose signal. For most people in most places, that is a minor inconvenience. For people in remote, rural, or coastal locations or in the event of a natural disaster, it can be a matter of life and death.

D2D changes that equation. By connecting a standard smartphone directly to a satellite in low Earth orbit (LEO), it extends mobile coverage to areas where building terrestrial infrastructure is commercially unviable or physically impossible. No specialist device. No additional hardware. Just the phone already in your pocket, connecting to a satellite passing overhead.

How it works

D2D services use existing licensed mobile spectrum, the same spectrum bands already allocated to mobile network operators for terrestrial use but extend that licence to allow a satellite to act as a base station in space. The satellite picks up the signal from the handset, routes it through a gateway on the ground, and connects it to the wider network.

The key technical development that made this possible was the miniaturisation of the radio payloads on the satellites themselves, specifically the ability to detect the very weak signals transmitted by a standard smartphone, which was not designed to reach orbit. SpaceX’s Starlink, AST SpaceMobile’s BlueBird constellation, and others have invested heavily in solving exactly this problem.

Current D2D services support messaging and data. Voice and SMS over D2D are in development, with some providers, including AST SpaceMobile, positioning their upcoming services around full voice capability from the outset.

What it is not

D2D is not a replacement for terrestrial mobile coverage. It does not deliver the speeds, latency, or reliability of a 4G or 5G ground-based connection. Ofcom’s quality definition for mobile coverage, a sustained 2Mbps downlink and the ability to sustain a 90-second voice call is not currently met by D2D services. It requires an unobstructed view of the sky, which means it does not solve indoor coverage gaps.

It is best understood as a complementary layer, a fallback service that activates when terrestrial coverage runs out, rather than a substitute for it. As Capacity has previously reported, this places D2D within a broader non-terrestrial network (NTN) strategy that operators and satellite providers are building alongside, not instead of, their ground-based infrastructure.

Where the market stands today

The UK became the first country in Western Europe to offer a live commercial D2D service when Virgin Media O2 launched O2 Satellite on February 26, 2026, using SpaceX’s Starlink Mobile constellation over licensed 1800 MHz spectrum. The service is priced at £3 per month or included free on high-end tariffs.

The results have moved faster than many anticipated. Analysis of Ookla signal scan data published in early 2026 found that within six weeks of commercial launch, the UK had become the third-largest D2D market in the world by unique user count, behind only the United States and Australia. Geographic clustering of usage tracks almost exactly onto Ofcom’s identified coverage not-spots, the Scottish Highlands and Outer Hebrides, the Welsh uplands, the Southwest peninsula, the Yorkshire Dales and North York Moors.

A second UK D2D service is on the way. Ofcom granted VodafoneThree a licence variation on 15 April 2026 to operate D2D on 900 MHz Band 8 using AST SpaceMobile’s BlueBird satellites. Customer trials are expected in summer 2026, with commercial launch targeted for the end of the year.

The US market, where T-Mobile launched the first commercial D2D service using Starlink, and Australia, where Telstra has partnered with Starlink, remain ahead in maturity. But the UK’s rapid ascent signals that regulatory clarity, rather than geography or population, is the primary determinant of market development speed.

Why regulation matters as much as technology

The UK moved first in Europe because Ofcom moved first. Its December 2025 framework authorised D2D in mobile spectrum through a combination of a handset licence exemption and operator licence variations, the first such framework in any European country.

The European Union faces a more complex challenge. D2D in harmonised mobile bands is not currently permissible under existing EU member state licences, which were built for terrestrial use. Progress is tied to decisions at the World Radiocommunication Conference in 2027, which will set the global framework for satellite-to-handset services across key spectrum bands. Until that process concludes, EU operators cannot move at the speed the UK has.

The key players

SpaceX Starlink is the most deployed D2D provider globally, operating through partnerships with T-Mobile in the US, Virgin Media O2 in the UK, and others. Its first-generation constellation supports messaging and low-throughput data.

AST SpaceMobile is building a broadband-capable constellation with BlueBird satellites designed to support voice, SMS and higher data speeds. Its partnerships include VodafoneThree in the UK and AT&T in the US.

Apple pioneered consumer awareness of satellite connectivity with its Emergency SOS via Satellite feature, introduced with the iPhone 14. While technically distinct from operator D2D services, it established mainstream consumer familiarity with the concept.

What comes next

The immediate trajectory is toward more capable services. As satellite constellations mature, with newer generation payloads offering greater cell capacity, broader spectrum support, and lower latency, the gap between D2D and terrestrial mobile quality will narrow.

Voice and SMS support over D2D will become standard. The question of whether D2D coverage can eventually be treated as equivalent to terrestrial coverage for regulatory purposes, including for emergency services, will become increasingly pressing for operators, regulators, and governments alike.

For a deeper look at how D2D messaging is laying the groundwork for satellite broadband, and how satellites and smartphones are converging across consumer and enterprise use cases, see Capacity’s earlier coverage of both topics.

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