TL;DR
- A data-only SIM provides mobile data but no voice calls or SMS; it is designed for tablets, MiFi routers, mobile dongles, and connected devices.
- UK operators and MVNOs offer data-only SIMs on rolling monthly or fixed-term contracts, with allowances from a few gigabytes to unlimited.
- Data-only SIMs can physically be inserted into a smartphone, but the phone will not be able to make or receive calls on that SIM.
- Monthly costs are often lower than equivalent-allowance standard SIMs because no voice or SMS infrastructure is provisioned.
- IoT and machine-to-machine (M2M) SIMs are a specialist sub-category with different commercial terms; consumer data-only SIMs are the everyday product.
The basic definition of a data-only SIM
A data-only SIM is a subscriber identity module that is provisioned by the mobile network for data transmission only. When the network registers the SIM, it assigns it an IMSI (International Mobile Subscriber Identity) and grants access to the packet-switched data service, but the SIM is not allocated a telephone number in the standard public switched telephone network sense. As a result, devices using a data-only SIM can access the internet over 3G, 4G, or 5G, but cannot place or receive voice calls through the conventional phone network, nor send or receive standard SMS messages.
This is a deliberate provisioning choice rather than a hardware limitation. The physical SIM card itself is identical to a standard SIM; the difference lies in how the mobile operator configures the account on its systems. Data-only SIMs are sometimes referred to as tablet SIMs, MiFi SIMs, or broadband SIMs in retail contexts, though all refer to the same underlying product type.
Devices that commonly use data-only SIMs
Tablets with cellular capability are perhaps the most common consumer use case. A tablet SIM slot accepts a nano-SIM or eSIM provisioned for data-only, allowing the device to connect to the internet without relying on a nearby Wi-Fi network or phone hotspot. Users who carry a tablet for work or travel frequently find a data-only SIM more convenient than managing tethering from a phone.
MiFi portable routers and fixed 4G or 5G home broadband routers are the other major category. These devices have no screen or call capability; they exist solely to provide internet access to multiple connected devices, so a data-only SIM is the natural and correct product. Mobile dongles — USB sticks that plug into a laptop and provide a cellular data connection — fall into the same category. Beyond consumer devices, machine-to-machine (M2M) and Internet of Things (IoT) applications use specialist data SIMs in connected sensors, vehicle trackers, smart meters, and industrial equipment; these typically operate under different commercial and technical terms than retail consumer data-only plans.
How data-only SIM plans are structured
UK mobile operators and mobile virtual network operators (MVNOs) offer data-only SIMs on broadly two contract structures: rolling monthly (often labelled “30-day SIM-only”) and fixed-term contracts, typically 12 or 24 months. Rolling plans offer flexibility — you can cancel at the end of any month — but frequently carry a modest price premium over equivalent fixed-term commitments. Fixed-term plans usually offer the lowest per-gigabyte cost in exchange for the commitment period.
Allowances vary widely. Small starter plans in the range of 5–15 GB per month suit light use such as email and occasional streaming on a tablet. Mid-range plans of 30–100 GB serve heavier tablet users or MiFi devices shared among a small number of users. Unlimited data plans are available on data-only SIMs from several UK operators, though “unlimited” plans typically carry a fair-use threshold above which speeds may be deprioritised during network congestion, as documented in operator terms and conditions. Ofcom's guidance on advertising requires that material limitations on “unlimited” services be clearly disclosed.
| Use Case | Device Type | Typical Monthly Data Need | Plan Structure |
|---|---|---|---|
| Casual tablet browsing & email | iPad / Android tablet | 5–15 GB | Rolling monthly |
| Portable Wi-Fi for 2–3 devices | MiFi router | 30–100 GB | Rolling or 12-month |
| Primary home broadband alternative | Fixed 4G/5G router | 200 GB–unlimited | 12–24 month |
| Occasional laptop connectivity | USB dongle | 5–30 GB | Rolling monthly or PAYG |
| Connected vehicle / IoT sensor | M2M device | Low (<1 GB typically) | M2M / enterprise contract |
Comparing data-only SIM costs to standard SIMs
Because a data-only SIM does not include the infrastructure overhead of voice minutes and SMS bundles, operators can often offer them at lower headline prices than a standard SIM-only plan with an equivalent data allowance. This is not universal — some operators price data-only SIMs at parity with standard plans — but competitive pressure in the UK mobile market, documented through Ofcom's annual Communications Market Report, has generally kept data-only pricing efficient. The practical saving varies depending on whether you need voice and messaging on the same device: if you are fitting a tablet that will never make calls, there is little reason to pay for a voice bundle.
PAYG (pay-as-you-go) data-only options also exist for genuinely infrequent use, though the cost per gigabyte on PAYG arrangements is typically much higher than on monthly plans. For anyone who expects to use more than a few gigabytes per month, a rolling monthly plan almost always represents better value than PAYG data.
Practical considerations when choosing a data-only SIM
Coverage is the first practical consideration: a data-only SIM on a network with poor coverage in your primary use locations delivers worse value than a slightly more expensive plan on a network with strong coverage there. Ofcom publishes interactive coverage maps at its Connected Nations resource, and each UK mobile operator is required to make coverage information publicly available. Checking predicted coverage at the specific postcode or location where the SIM will primarily be used is strongly recommended before committing.
SIM format is a secondary consideration. Most devices now use nano-SIM; many newer tablets, routers, and MiFi units also support eSIM, which allows the profile to be downloaded remotely without a physical card. If your device supports eSIM, confirming that the chosen operator offers eSIM provisioning for data-only plans before purchase avoids a compatibility issue. Physical SIM cards are usually supplied as a triple-cut card covering standard, micro, and nano sizes.
What this means in practice
Marcus is a secondary school teacher in Leeds who uses a cellular-capable iPad for marking and lesson preparation during his commute. He previously relied on his phone hotspot, but found managing two devices during a busy commute inconvenient. He took out a rolling monthly data-only SIM for his iPad, choosing the network with the strongest coverage on his specific rail route by consulting the Ofcom coverage checker. He opted for a 20 GB monthly plan, which comfortably covers two daily commutes of heavy PDF use and occasional video. His phone contract is unchanged; the iPad SIM costs him a modest addition to his monthly outlay, and he no longer needs to remember to activate his hotspot each morning. When his usage pattern changed over summer, he cancelled the rolling plan without penalty and reactivated in September.
Related Guides
How we verified this
This article draws on Ofcom's Connected Nations reports, Ofcom's Communications Market Reports, and Ofcom's consumer guidance on mobile contracts and SIM-only plans. Technical definitions of SIM provisioning and M2M/IoT SIM categories reference GSMA technical specifications. Coverage checker references point to Ofcom's published interactive mapping tool.
Disclaimer: Kaeltripton.com is an independent UK editorial publisher. We are not regulated by Ofcom or the FCA and we do not sell or arrange mobile services, insurance, or financial products. This content is for general information only and is not legal, financial, or technical advice. Rules, prices, and operator policies change. Verify the current position with Ofcom, GOV.UK, the ICO, or your provider before acting. ICO registered ZC135439. Last reviewed: 2026-06-05.
Frequently Asked Questions
What is a data-only SIM?
A data-only SIM is a SIM card provisioned by a mobile network exclusively for data services. It allows the device it is inserted into to connect to the internet over 4G or 5G, but does not provide a telephone number, voice call capability, or standard SMS messaging. It is designed for tablets, MiFi routers, dongles, and other connected devices that do not need to make calls.
Can I put a data-only SIM in a phone?
Physically, yes — a data-only nano-SIM fits the same slot as a standard SIM. The phone will connect to mobile data normally. However, you will not be able to make or receive voice calls or send and receive standard SMS messages through that SIM, because the account is not provisioned for voice. Mobile data apps, messaging apps that use data (such as WhatsApp), and internet browsing will work as normal.
Are data-only SIMs cheaper than standard SIMs?
They often are, because the operator does not provision voice call infrastructure for the account. However, pricing varies across operators and plans. On rolling monthly deals in particular, data-only SIMs can represent good value for tablets and MiFi devices. The difference is less pronounced on fixed-term contracts where operators bundle large data allowances into standard SIM-only deals at competitive prices. Always compare current plan pricing directly.
What devices use data-only SIMs?
The main consumer devices are cellular tablets (such as iPads and Android tablets with a SIM slot), MiFi portable Wi-Fi routers, fixed 4G/5G home broadband routers, and USB mobile dongles. Beyond consumer products, machine-to-machine and IoT applications — including vehicle trackers, smart meters, and connected sensors — use specialist data SIMs under separate commercial arrangements.
Do data-only SIMs include any calls or texts?
Standard data-only SIMs do not include voice call minutes or SMS bundles. Some operators offer hybrid plans that include a small SMS allowance alongside data, particularly for tablet SIMs, but this is not universal. If you need voice calls and texts alongside data on the same SIM, a standard SIM-only plan is the appropriate product. Data-only SIMs are designed for devices where call and SMS capability is either unnecessary or handled through data-based apps.
