Prepaid data SIM: keep the data running without finding a shop
A data-only SIM in a tablet, a travel router or a spare handset still needs topping up — and it cannot call a hotline or read a voucher SMS to do it. Load a data bundle onto its number from a browser instead, in 42 countries.
There is no card to order and nothing to post: MobileTopUP is a top-up service, so it adds credit to a prepaid line that already exists. Get the SIM from the operator or a local seller, then use this page to keep data on it. We do not issue eSIM profiles either — what we deliver is credit to a mobile number, whichever form the SIM takes.
What a prepaid data SIM is
A prepaid SIM sold for data and nothing else. Calls and texts are usually barred, you pay before you use it, and when the allowance or its validity window ends the data stops until you load more.
| Aspect | Data-only prepaid SIM | Standard prepaid SIM | Postpaid contract |
|---|---|---|---|
| What it carries | Mobile data. Voice and SMS are normally switched off. | Data, calls and texts drawn from one balance. | Whatever the monthly plan bundles. |
| How you pay | In advance, a bundle at a time. | In advance, as airtime or a bundle. | Monthly in arrears, after a credit check. |
| When it stops | Allowance used up, or the validity window closes. | Same, though credit also drains on calls and texts. | It does not stop — it keeps billing. |
| Usually lives in | Tablets, laptops, routers, cameras, a spare travel device. | A phone someone uses every day. | A phone on a long agreement. |
Weighing prepaid against a contract in general? Our guide to prepaid and postpaid SIM cards covers the trade-off for a main phone line.
Where a data-only SIM usually ends up
Four devices account for most of them, and each one changes how you top the SIM up.
Tablets and laptops
A cellular iPad or a laptop with a SIM tray. The number is usually readable in the device settings, so topping it up is the easy case.
Home and travel routers
A 4G or 5G box sharing one SIM with everything in the room. The number lives in the router's admin page rather than on any screen.
A second travel device
A local data SIM bought on arrival, kept alive from home between trips so the number and any remaining allowance survive.
Cameras and trackers
Dashcams, security cameras, vehicle trackers. Consumer SIMs top up normally; dedicated machine-to-machine plans often cannot — which device SIMs have a line at all tells the two apart.
Find the number before you pay
This is the step that stops people. A top-up is delivered to a mobile number, and a data SIM sitting in a router has never shown you one. Four reliable places to look:
Operators often print the number on the plastic holder, near the long serial. If you kept the packaging, start here — it takes ten seconds.
On Android it is usually under Settings, About phone, SIM status; on an iPad, under Settings and Cellular. Some operators never write the number to the SIM, so the field can be blank.
Sign in to the router in a browser and open its SIM or status page. Most 4G and 5G routers show the number there along with the signal and the current network.
Whoever the SIM was registered to can see it in the operator's app or web account. This is also the fastest way to confirm the line is still active.
One case has no answer: some machine-to-machine and IoT data plans are sold without a public number, or with the line locked to the reseller who supplied it. Those cannot be topped up by a third party. If you order one anyway the operator rejects it, and the full amount comes back to your card.
Data bundle or plain airtime?
Both can end up as data, but on a data-only SIM they behave very differently. Which of the two is offered for a given number is the operator's catalogue, and it appears once the number is entered.
Data bundle — usually the right pick
A fixed allowance at the operator's own bundle price, applied to the line straight away. Nothing else to activate on the device.
- Bought as a block of data at the operator's bundle price, which is normally cheaper per gigabyte than burning through credit.
- Carries its own validity window — worth checking against how long you actually need the data to last.
- Needs no SMS or keypad code at the far end — which matters when the SIM lives in a router.
Airtime — the fallback
General credit on the line. Useful when the operator sells no bundle for that number, but it asks more of you afterwards.
- On many networks, data used without a bundle is billed at a higher out-of-bundle rate.
- Turning that credit into a bundle usually means sending a code or using the operator app — awkward on a device with no dialler.
- It does keep an idle line alive, which is sometimes the whole point.
Two clocks run at once
People search for a data SIM that lasts 365 days and then get caught by the second clock. Both of them belong to the operator, not to us.
Long-validity bundles do exist on plenty of networks, from a few days up to a year. We neither set those windows nor price them — what you can buy for a given number is whatever that operator currently sells, and you see what each option includes before you pay. What we can do is keep the second clock from running out.
See what is available for a numberThe bundle clock
How long the allowance you just bought stays usable. When it expires, any data left in it normally goes with it — so buying a larger bundle than you can use inside the window is money parked, not saved.
The SIM clock
Prepaid lines are deactivated after a stretch with no paid activity, and the length varies a lot between operators. A small top-up before that date keeps the number. Once the line has lapsed the operator rejects the order and we refund in full — recovering the number is then a conversation with the operator, not with us.
Not sure where your current plan stands? Checking when a recharge runs out walks through the usual ways to read the expiry date off a line.
Loading data onto the SIM
Same flow as any top-up, with one extra check at the start.
- 1
Country, then number
Pick the country the SIM belongs to — not the country you are sitting in — and enter the number with its international code.
- 2
Choose the data option
The operator is detected from the number and its catalogue loads. Check what an option includes and what the total comes to before you confirm.
- 3
Pay and watch it land
Card, Apple Pay or Google Pay. Most orders are credited 5 to 60 seconds later, and you get the operator's reference code on screen and by email.
Data abroad: roam or buy local?
A data-only SIM is often bought to avoid roaming charges. Whichever way you go, the top-up works the same — you can load a foreign SIM from home, and your home SIM from abroad.
Roaming keeps one number and one bill but is metered by your own operator. A local data SIM is usually cheaper for a long stay, at the cost of a second number that then needs keeping alive between trips — which is exactly what a small top-up on a schedule is for.
When the data does not appear
Four things go wrong, and only two of them are about the top-up at all.
Paid, but nothing on the line yet
Give it a few minutes first — some operators batch loads at busy hours. Anything not credited within 30 minutes is re-queued automatically, and if the retry fails too the full amount goes back to your card without you asking.
The operator rejected it
A SIM that is deactivated, expired, converted to postpaid, roaming-only or blocked cannot take credit. We refund in full and email you the reason the operator returned, which is usually enough to know what to ask them.
Bundle landed, device still offline
Now it is the device. Check mobile data is on, the APN matches what the operator publishes, and — on a SIM used outside its home country — that data roaming is enabled. No bundle can override a setting on the hardware.
The number was wrong
Easy to do when you read it off a router page. Contact support within 24 hours: once the payment has reached the operator, recovery is best-effort and depends on that operator's reversal policy.
Data SIM questions
Payments, refunds and account questions live in the help centre.
Open the help centreDo you sell prepaid data SIM cards?
No. MobileTopUP is a top-up service — nothing is shipped and there is no card to order. Buy the SIM from the operator or a local seller, then use the number on it here to keep data loaded.
Can a data-only SIM be topped up if it cannot make calls?
Yes. Voice being barred does not matter: the top-up is delivered to the line by the operator, not by anything the device has to send. You only need the number the SIM was issued with.
Is there a prepaid data SIM that lasts 365 days?
Some operators sell bundles with validity that long, others stop at a month. We do not set or price those windows. What you can buy for a given number is whatever that operator currently sells, and you see what each option includes before you pay.
Can I top up the SIM in a router or a tablet?
Yes, as long as it is a normal consumer prepaid line and you know its number. Dedicated machine-to-machine or IoT plans are the exception — those are often locked to the reseller and get rejected.
Can I load a data SIM that belongs to another country?
That is the usual case here. Choose the country the SIM belongs to, enter the number with its international code, and pay from wherever you are. Coverage runs to 42 countries and 230+ operators.
What about an eSIM?
We do not issue eSIM profiles. A top-up is delivered to a mobile number, so what decides whether it works is the number and its operator, not whether the SIM is plastic or downloaded.
Where to go next
Wider than a data SIM, or narrower than one.
The formal versions sit with the policies: delivery covers timings, rejected SIMs and automatic retries, and billing and refunds covers what the price pays for, the receipt and how a refund is timed.
Got the number? Load the data.
Enter it with the country code and the operator's data options appear. Most orders are credited in under a minute.