SIM Only Plans
Data, calls, and texts — no handset cost. Almost always cheaper than a phone contract for the same allowance. Here is everything you need to know.
A SIM Only plan gives you a monthly allowance of mobile data, calls, and texts on a SIM card — with no handset included. You use your existing smartphone. Because you are not paying off a new phone's cost through your monthly bill, SIM Only plans are almost always significantly cheaper than Pay Monthly phone contracts for an equivalent data allowance. On a typical large-data plan, the saving is often £10–£20 per month — which is £120–£240 per year, or £240–£480 over the typical 24-month period when a phone contract would otherwise be running.
Think of the difference this way: a Pay Monthly contract is like leasing a car with all insurance and servicing bundled in. SIM Only is paying purely for fuel. If you already have a car you are happy with, paying just for fuel makes much more financial sense.
Most people. Specifically: anyone whose current phone is under two to three years old and working well; anyone who has just finished paying off a phone contract and is now on the same tariff with no more handset to pay off (the most expensive mistake in UK mobile — continuing to pay the same amount after the phone is fully paid); anyone who buys phones outright, refurbished, or from a manufacturer directly; and anyone who values the flexibility to switch networks easily without a large exit fee. The only strong argument for a phone contract over SIM Only is if you want a brand-new flagship smartphone without paying £800–£1,200 upfront.
SIM Only plans come in two main contract structures. A 30-day rolling plan has no minimum term — you can give 30 days' notice and leave at any time with no exit fee. This maximum flexibility is usually slightly more expensive per month than a fixed-term deal. A 12-month contract commits you for one year in exchange for a lower monthly price — typically £1–£3/month cheaper than the equivalent rolling plan. Some networks offer 1-month contracts (essentially the same as 30-day rolling) and occasionally 24-month SIM-only deals at the lowest monthly price, though long SIM Only commitments are less common. If you are unsure about a network's coverage in your area, start with a rolling plan. Once satisfied, switch to 12-month for the lower price.
5G connectivity is included at no extra cost on SIM Only plans from all major UK networks — EE, O2, Three, Vodafone, and all the major MVNOs. There is no separate "5G premium tier" to pay for. You simply need a 5G-capable smartphone and to be in an area with 5G coverage. If your phone is a 4G-only model, it will continue to work perfectly on the 4G network with no issue. Check whether your device supports 5G in its technical specifications or the manufacturer's website before upgrading a plan expecting 5G access.
Almost all UK SIM Only contracts include an annual price rise clause — your monthly bill will increase once per year, typically in April. Under Ofcom's pounds-and-pence transparency rules (in force from 17 January 2025), networks must state the exact monetary amount of any price rise at the point of sale, in your pre-contract information. You must be able to see the specific rise before you sign. The major 2026 rises: EE SIM Only voice plans +£2.50/month each March; O2 Airtime Plans +£2.50/month each April; Three varies by plan tier; Tesco Mobile approximately 6% (but frozen on Clubcard Price deals). If the rise was not disclosed and you received notification mid-contract, you have a 30-day window to exit without penalty.
If you currently have a phone contract and want to move to SIM Only: if you are staying with the same network, call their customer retention team — they typically offer reduced SIM Only rates to keep you. If you want to switch networks and keep your number, text PAC to 65075 (free, within 60 seconds). Give the code to your new network when signing up. Your number transfers within one working day. Your old contract ends automatically. Before signing anything, check your phone is unlocked (text your current network — unlocking is free and mandatory for all phones sold since December 2021, and free for older devices on request).