Compare Mobile SIM Plans in United Kingdom

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1. Penny Pro · Talk Home Mobile · £0 /month
2. Prepay PAYG - The 1p Tariff · 1pMobile · £1 /month
3. 5GB Plan · Lebara · £1.48 /month
4. 10GB Plan · Lebara · £2.38 /month
5. 80GB · iD Mobile · £2.50 /month

What is a SIM-only deal in the UK?

A SIM-only deal gives you a mobile plan — data, calls, and texts — without a new phone. You keep your existing handset (or buy one separately) and pay only for the airtime. Because there's no device cost bundled in, SIM-only plans are significantly cheaper than phone contracts, typically saving £15–£30 per month compared to a handset deal with the same allowances.

The UK mobile market is served by four main network operators — EE, Three, Vodafone, and O2 — plus a thriving ecosystem of MVNOs (Mobile Virtual Network Operators) including giffgaff, VOXI, iD Mobile, Lycamobile, Lebara, and Asda Mobile. MVNOs use the infrastructure of the big four but often undercut them on price, making the UK one of Europe's most competitive mobile markets.

Benefits of choosing a SIM-only deal

Lower monthly cost — Without a phone to finance, SIM-only plans start from as little as £5/month for basic plans with 5–10 GB, rising to around £20–£26/month for unlimited data on a major network.

Flexibility — Many UK plans offer 30-day rolling contracts, meaning you can switch or cancel anytime. Longer 12-month, 18-month, and 24-month contracts often come with lower monthly rates or more data as a trade-off for commitment.

5G at no extra cost — Most UK operators now include 5G access on SIM-only plans at no additional charge, provided you have a 5G-capable device and are in a 5G coverage area. EE, Three, Vodafone, O2, and many MVNOs all offer 5G.

Keep your number — Switching provider is straightforward in the UK thanks to the PAC (Porting Authorisation Code) system. You can request a PAC via text and your number transfers within one working day.

Contract types in the UK

30-day rolling — Maximum flexibility. Cancel or change anytime with 30 days' notice. Popular with giffgaff, VOXI, Lycamobile, and Lebara. Ideal if you're unsure how long you'll need a plan or want to try a network before committing.

12-month contracts — A good balance of price and commitment. Common with iD Mobile, Asda Mobile, and O2. Often cheaper per month than rolling plans.

18-month and 24-month contracts — The lowest monthly rates, offered by EE, Three, and giffgaff. Best if you're happy to commit for the long term. Watch out for annual price rises (see below).

Annual price rises

A key consideration in the UK market is mid-contract price increases. Most major operators (EE, Three, Vodafone, O2) increase monthly prices annually — typically by CPI inflation plus an additional 3.9%. This means a £20/month plan could rise to £22+ after the first year. Some MVNOs like iD Mobile and giffgaff guarantee no mid-contract price rises, which can represent better value over a 24-month term.

EU roaming after Brexit

Since the UK left the EU, roaming guarantees are no longer legally required. However, most UK networks still include EU roaming at no extra cost, subject to fair-use data limits (often 25 GB per month). Some operators may charge for roaming or apply daily caps, so check the specific terms of your plan before travelling.

UK mobile network operators

EE is the UK's largest mobile network, part of BT Group. EE consistently ranks highest for 4G and 5G coverage and speed. SIM-only plans include features like data gifting to family members, and EU roaming is included as standard.

Three is known for generous unlimited data plans at competitive prices. Three pioneered unlimited data in the UK and offers strong 5G coverage in urban areas. The Three+ rewards app provides perks and discounts for customers.

Vodafone offers reliable UK-wide coverage and now benefits from network sharing with Three following their merger. Vodafone Together bundles allow families to combine broadband and mobile for additional savings, with plans from £16/month when bundled.

O2, part of Virgin Media O2, is popular for its O2 Priority rewards programme, which gives customers early access to event tickets and exclusive offers. O2's 5G rollout covers major UK cities.

MVNOs — budget-friendly alternatives

giffgaff runs on the O2 network and is famous for its no-contract approach, no credit checks, and community-driven support model. Plans are available on both 30-day rolling and 18-month terms, with bonus data often included on longer contracts.

VOXI is Vodafone's sub-brand aimed at younger users, offering 30-day rolling plans with unlimited social media, music, and video streaming data that doesn't count toward your allowance.

iD Mobile uses Three's network and has been endorsed by Which? for great value. A standout feature is the guarantee of no annual price rises during your contract, plus eSIM support.

Lycamobile and Lebara specialise in affordable plans with international calling minutes, making them popular with expat communities and international callers. Both offer 5G, eSIM, and no credit checks.

Asda Mobile runs on Vodafone's network with 99% UK population coverage. Features include data rollover (unused data carries to next month), Asda Rewards cashback, and the ability to upgrade your plan mid-contract.

Frequently asked questions

Can I keep my phone number when switching?
Yes. Text PAC to 65075 from your current SIM to receive a Porting Authorisation Code. Give this to your new provider and your number will transfer within one working day.

Do I need a credit check for a SIM-only plan?
Postpaid contract plans (12, 18, 24 months) typically require a credit check. Many MVNOs — including giffgaff, VOXI, Lycamobile, and Lebara — offer plans with no credit check required, usually on 30-day rolling terms.

What's the difference between 4G and 5G?
5G offers faster speeds (typically 100–300 Mbps, up to 1 Gbps in ideal conditions) and lower latency than 4G. Most UK operators include 5G at no extra cost on SIM-only plans. You'll need a 5G-capable phone and be in a 5G coverage area to benefit.

What does "unlimited" data really mean?
Most UK unlimited data plans are truly unlimited for personal use. Some operators apply a fair-use policy (e.g., speeds may be reduced after 600 GB/month on EE) to prevent abuse, but for the vast majority of users, unlimited means unlimited.

Mobile SIM Plans in United Kingdom — FAQ