30-Day SIM Only Deals March 2026

Our best 30-day SIM deals this week

What is a 30-day SIM?

A 30‑day SIM‑only deal is a mobile plan that gives you a monthly allowance of data, minutes, and texts without a long‑term contract. Instead of committing for 12 or 24 months, you pay month‑to‑month and can cancel or switch provider with typically 30 days’ notice.

These plans usually operate on a rolling contract, meaning your plan automatically renews each month until you decide to change or cancel.

How do 30‑day SIMs work?

• You choose a monthly allowance (data, minutes, texts)
• You pay a fixed monthly fee
• Your plan renews every 30 days
• You can cancel, switch, or upgrade with short notice (usually 30 days)

Most providers run credit checks, but some (like PAYG-style SIMs) may not.

Which networks offer 30-day SIMs?

Almost all household-name networks offer short-term 30-day SIMs, as do a range of lesser-known mobile networks, too.

Below we’ve picked out some of our best 30-day SIMs, alongside a snapshot of what each network has to offer.

Virgin Mobile 30-day SIM-only deals

All of Virgin Mobile's SIM-only deals are on 30-day rolling contracts, with data allowances ranging between 3GB and 100GB per month.

As well as unlimited calls and texts, you get some handy extras, such as data rollover, EU roaming and data-free messaging on WhatsApp, Twitter and Facebook.

SMARTY 30-day SIM-only deals

With a service based on Three’s network infrastructure, SMARTY specialises in low-cost plans with the USP of getting money back for any unused data.

Three 30-day SIM only deals

As well as 12-month and 24-month SIM plans, Three also offers a selection of one-month SIMs. Customers also get access to Three+ Rewards, Three’s rewards app that has exclusive offers from plenty of high-street brands. Not to mention, it boasts some of the fastest 5G speeds in the UK.

Vodafone 30-day SIM-only deals

All of Vodafone's 30-day plans come with a three-month free trial of SecureNet security software, as well as weekly offers and discounts via the VeryMe Rewards programme.

iD Mobile 30-day SIM-only deals

iD Mobile offers a wide selection of well-priced 30-day SIMs, with data allowances ranging from 5GB all the way to unlimited data. Coverage is provided by Three, and there’s inclusive roaming in 50 locations worldwide.

How to choose the right plan

When comparing deals, consider:

• Your data usage - The average UK user consumes around 5–7GB per month, but streaming, gaming, or hotspot use can increase this significantly.
• Coverage in your area - Network performance varies by location — check coverage maps before switching.
• Extras and perks - Some providers include benefits like data rollover, roaming, or subscriptions.
• Price vs flexibility - Short contracts offer freedom, but longer deals may be cheaper overall.

Pros and cons of 30-day SIMs

Pros

• Flexibility - Switch networks or deals without long contracts.
• Low commitment - Ideal for short-term needs or testing a network.
• Quick upgrades - Easily move to higher data plans if your usage changes.

Cons

• Higher monthly cost - Often more expensive per month than longer contracts.
• Fewer perks - Some benefits (e.g., bundled subscriptions) are more common on longer deals.
• Price changes - Monthly pricing can change more frequently.

Alternative SIM only plans

Not sure if a 30-day SIM is right for you? Perhaps one of these SIMs will suit you better:

• 12-month SIMs
• Pay as you go SIMs
• Bad credit SIMs
• Cheap SIMs
• Unlimited data SIM only

Which networks offer cheap SIMS?

Here's a selection of networks that offer cheap SIM only deals and a glimpse of what they've got to offer:

• O2
• Vodafone
• Three
• Lebara
• VOXI
• iD Mobile
• giffgaff
• SMARTY

How do I find a 30-day SIM plan?

The best and most practical way to find a suitable 30-day SIM is to work out how much data you think you’ll need. According to a 2022 Ofcom report, the average user in the UK got through 5.6GB of data per month.

But to find out for sure how much you use, take a look in your network’s app on your smartphone (assuming you’ve downloaded it) or get in touch with your network.

Are 30‑day SIMs truly contract‑free?

They are contract-based but short-term. You typically need to give 30 days’ notice to cancel.

Will there a be a credit check on a 30-day SIM?

That depends on the network. While smaller, more budget-friendly networks (such as the likes of VOXI, Lebara and SMARTY) don’t apply credit checks, some networks may still check your credit score.

However, what we can see is that credit checks for 30-day SIMs will be much less stringent and easier to pass than those for pay monthly phone contracts or even those for 12-month or 24-month SIMs.

Do I have to top up 30-day SIMs every month?

There’s no need to top up your allowance every month when you’re signed up to a 30-day SIM. Your allowance will renew every 30 days automatically and will continue to do so until you tell your network you’d like to cancel.

Do SIM cards expire if not used?

Yes, SIM cards do expire if they haven’t been used in a certain period of time. Depending on the network, an inactive SIM card will usually expire after 90 to 180 days.

Most networks stipulate that you need to carry out a chargeable activity on your SIM at least once every 90 to 180 days (this period varies depending on the network). So, as long as you use some data, make a chargeable call or send a text within that time, your SIM card won’t expire.

Can I keep my number?

Yes — you can transfer your existing number using a PAC code from your current provider.