Card Machines That Work Without WiFi: SIM Card Readers Compared

If you take payments in a field, a van, a church hall or a customer's kitchen, WiFi isn't something you can count on. The good news is you don't need it. Plenty of card machines work on mobile data instead, either with their own SIM card or through your phone.

Here are your options, what they cost and how to make sure they actually work where you trade. Prices are from providers' official UK websites, checked October 2026.

Your three options

SIM card machines

A SIM card machine has a mobile data connection built in, just like a phone. It doesn't need WiFi or a phone nearby. Most also connect to WiFi, so you can use whichever is stronger.

Watch for data charges. Some providers include mobile data free, others charge for it. Stripe, for example, charges £7 per reader per month for cellular connectivity. SumUp includes a free SIM with its Terminal. Always ask.

Our page on the PAX A920 Pro and our myPOS card machine guide cover two more SIM based options.

Phone paired readers

These small readers connect to your phone by Bluetooth and use your phone's internet connection, whether that's mobile data or WiFi. If your phone has signal, the reader works.

They're the cheapest way to take card payments without WiFi. The downsides are that your phone must stay charged and nearby, and you're using your own data allowance, though card payments use very little.

Tap to Pay

Tap to Pay turns your phone into a contactless reader using its own data connection. There's nothing to buy. It's ideal as a backup, but it only takes contactless, so a customer asked for a PIN may struggle unless your provider supports PIN entry on screen.

What about no signal at all?

Some card machines have an offline mode. They store payments when there's no connection and send them once you're back online. It sounds perfect for a remote festival, but there are risks:

• The payment isn't checked by the bank at the time. If the card's later declined, you may not get the money.
• Not every provider offers it. And those that do may limit the amount or number of offline payments.
• Some cards won't work offline.

If you regularly trade with no signal, offline mode is worth asking about, but treat it as a last resort rather than a plan.

Getting the best signal

• Check coverage at your usual spots. Before buying, test your phone's signal where you trade. If one network is poor, ask which networks your terminal's SIM can use. Some SIMs roam across several networks.
• Hold it high. Signal is often better standing up, near a window or outside.
• Avoid metal boxes. Vans, trailers and steel buildings can block signal. Step outside if needed.
• Use your phone's hotspot. If your terminal has WiFi and your phone has signal on a different network, a hotspot can rescue a payment.
• Keep it charged. Searching for signal drains the battery faster.

Who needs a card machine without WiFi?

Tradespeople. Taking payment at the customer's house means relying on mobile data, not their WiFi. A SIM terminal or phone reader both work well.

Taxi and private hire drivers. A SIM terminal is the most reliable choice. Our guide to card readers for taxi drivers covers this in detail.

Market traders and events. Signal can drop when thousands of people are in one field. Have a backup, such as a second reader on a different network.

Mobile hairdressers, beauticians and dog groomers. A phone paired reader is usually plenty.

Delivery and takeaway drivers. A SIM terminal that staff can carry without needing their own phones.

SIM terminal or phone reader: how to decide

Choose a SIM terminal if:

• Staff take payments and you don't want them using their own phones.
• You need printed receipts.
• Your phone's battery already struggles to last the day.
• You want one device that just works, without pairing.

Choose a phone paired reader if:

• You're a sole trader and always have your phone on you.
• You want the lowest upfront cost.
• You take payments only now and then.

Many mobile businesses end up with both: a SIM terminal as the main device, and a cheap reader or Tap to Pay as a backup on a different network. If one network drops out at an event, the other often still works.

Before you buy: a quick test

Download your chosen provider's app and set up Tap to Pay, if it's available, before you order hardware. Take a few small test payments at the places you usually trade. If your phone struggles for signal there, a SIM terminal on another network might be the better buy.

Cost comparison

Here's how the costs look over a year for a mobile business taking £2,000 a month by card.

Fees use published in person rates on UK consumer cards. Hardware ex VAT. In this example, a phone paired reader is the cheapest, while a SIM terminal costs a bit more but frees your phone.

FAQs

Can I use a card machine without WiFi?

Yes. SIM card machines use mobile data, and phone paired readers use your phone's connection. Neither needs WiFi.

Do SIM card machines cost extra each month?

Sometimes. SumUp's Terminal includes a free SIM, but some providers charge for data. Stripe charges £7 per reader per month for cellular connectivity.

Which mobile network do card machine SIMs use?

It depends on the provider. Some SIMs can switch between networks. Ask before you buy, especially if you work in rural areas.

Can I take card payments with no signal at all?

Some machines have an offline mode that stores payments and sends them later, but there's a risk the payment is declined later. It's best as a last resort.

Does a phone card reader use a lot of data?

No. Each payment uses a very small amount of data.

What's the cheapest card machine without WiFi?

A phone paired reader such as the Square Reader at £19 ex VAT, using your phone's mobile data. Tap to Pay costs nothing to start.

Can I use my phone's hotspot for a card machine?

Yes, if the machine connects to WiFi. Turn on your phone's hotspot and connect the card machine to it, just as you would to any WiFi network.