Setting up a 4G router with a data SIM

To set up a 4G router, install a compatible SIM, activate it in the ThingSIM portal, enter the APN shown for that SIM and test mobile data. Do the first test before connecting every laptop or device that will eventually use the router, so you can see whether the basic connection works.

For a router carrying a handful of devices or broadband backup traffic, UK 4-network 5 GB is a starting point at £8.85 per active SIM per month. It is a fixed allowance, so decide what the router must carry rather than treating it as an unlimited broadband replacement.

Check the router before ordering

Confirm that the router accepts the type of SIM you intend to buy and supports the required mobile networks. Read the manual for the exact model. Do not assume that a router with a physical slot can also install an eSIM, or that every version of a product has the same mobile hardware.

A physical ThingSIM is a trio SIM, with mini, micro and nano sizes to pop out. It is posted to UK and EU addresses. An eSIM is delivered as a QR code minutes after ordering and needs a compatible installation method on the router. Either format costs £2.00 per SIM once. eSIM or physical SIM helps with that choice.

Installation checklist

1. Follow the manufacturer's instructions for fitting the physical SIM, including powering the router down if required. Use the specified size and orientation. For eSIM, follow the router's supported QR code installation process.
2. Identify the installed SIM in the ThingSIM portal. Activate it when you are ready to configure and test the connection; billing starts that day.
3. Copy the APN displayed against that SIM. Enter it in the router's cellular connection profile and save the profile as instructed by the router manufacturer.
4. Check which SIM slot or profile is selected for mobile data. Review the data roaming setting and any PIN prompt using the manufacturer's guidance.
5. Put the router in a practical temporary position with its antennas fitted as instructed. Keep it accessible while you compare possible locations.
6. Connect one test device to the router. Confirm that its test traffic uses mobile data rather than another broadband or Wi-Fi connection.
7. Run the intended application, then review SIM usage in the portal. Record the working settings and position before adding the rest of the equipment.

The APN setup guide explains where the setting belongs. Keep the APN distinct from Wi-Fi credentials: one configures the mobile connection and the other controls how local equipment joins the router.

Choose a position before mounting

Try more than one location, including a higher position or one nearer a window where practical. Avoid deciding from signal bars alone. Repeat a real data task and note whether it completes in each position. Test with the cupboard or equipment enclosure closed if that is how the router will operate.

Metal and concrete are reasons to investigate placement carefully. If the router supports external antennas, ask its supplier which antenna and connections suit the model and installation. ThingSIM does not supply antennas or site surveys. Arrange any mounting work separately and test the proposed arrangement before fixing it permanently.

UK 4-network roams across O2, Vodafone, Three and EE, using whichever is strongest where the device is. UK 3-network leaves out EE and costs less. Extra network choice helps when the best operator differs by location, but still test the finished installation.

Decide what may use the connection

Make a list of essential traffic: perhaps a payment terminal, a few status reports and access to a business application. Then list optional traffic, such as software downloads, camera viewing and staff browsing. Use router controls where available to keep optional activity within the allowance you have chosen.

ThingSIM offers 50 MB, 250 MB, 1 GB and 5 GB monthly plans. A router serving only a small telemetry device may need less than the recommended 5 GB. A busy shared connection may exceed it. Measure a representative period and include setup downloads and occasional updates in the estimate.

At the allowance limit, the SIM pauses rather than charging overage. If you are on a smaller plan, you can upgrade immediately, paying only the difference for the rest of the month. At 5 GB, the largest listed allowance, wait for the reset and review the workload. Plan changes and usage are available in the portal.

Test the backup role separately

For router failover, first prove mobile data works on its own. Then configure the router's broadband and mobile priorities according to its manual. Test loss of broadband, run the essential applications, and confirm the router returns to the intended connection afterwards.

Use 4G backup for a broadband line to plan that test. Keep a short record of the steps so you can repeat it after changing the router or the devices connected to it. General ordering and account questions are covered in help.

Common questions

Can any 4G router use an eSIM?

Only use an eSIM if the router explicitly supports installing it. Otherwise choose the physical SIM size specified by the manufacturer.

Is 5 GB enough for a router?

It depends on the equipment and traffic behind it. Estimate essential use and updates, then check actual SIM usage in the portal.

Does inserting the SIM start billing?

Billing starts when you activate the SIM in the ThingSIM portal. SIMs arrive inactive, so insertion and activation are separate steps.