Choosing the right SIM Only deal for you

Wondering whether to change to a Pay Monthly SIM when your contract ends? Our SIM guide is here to help. Here's how to choose the best SIM for you

As the life cycle of smartphones increases, people are holding on to their phones for longer. As a result, SIM Only deals are becoming more popular.

What is a SIM? In a nutshell, a traditional SIM is a small plastic memory card that slots into your phone. It stores key information, like your phone number and other people’s contacts, and it lets you make and receive calls and texts and use data on your phone. A SIM Only deal means you get a new SIM without a new phone. So, you can keep using your current device while getting the benefits of a shiny new deal.

Of course, lots of us are keen to upgrade to a new smartphone when we get the chance. But if you don’t mind sticking with your current phone when your contract ends, a SIM Only deal can be a simple way to save money.

Not sure which O2 SIM you need? Here’s everything you need to know about choosing the best SIM Only deal for you.

What is a Pay Monthly SIM?

It’s a SIM that you pay for monthly. You can choose between 24-month, 12-month and 30-day Plans depending on what suits you. Plus Plans are also available to new and upgrading O2 Pay Monthly customers on SIM Only contracts. Find out more about Pay Monthly SIM Only deals.

Why would a Pay Monthly SIM be right for me?

Our Pay Monthly SIM Only deals are some of the most affordable ways to access our network and perks. Get VIP treatment, with freebies and prize draws on Priority. And never miss a moment, with free O2 WiFi when you're out and about. If you choose one of our SIM Only Plus Plans, you’ll get all the best parts of O2 at even greater value. They come with benefits like roaming at no extra cost in 75 countries – we’re the only major network that’s not reintroducing EU roaming charges, up to 25GB. Plus Plan customers can also choose an Extra for up to six months, such as Disney+ or Amazon Prime, on us.

What is a Pay As You Go SIM?

It’s a traditional SIM. Our O2 Pay As You Go SIM deals include Rolling Plans and Big Bundles. The contract-free Rolling Plans give you a monthly allowance of minutes, texts and data that refreshes after each automatic payment. With a Big Bundle SIM Only deal, you top up your SIM each month with a certain amount of credit. Unused data can be rolled over to the next month, depending on which Big Bundle Plan you choose. Find out more about Pay As You Go SIM Only deals.

Why would a a Pay As You Go SIM be right for me?

Our best Pay As You Go SIM deals allow you to tailor data to suit your lifestyle, customising the cost of your SIM to match your budget. They’re super flexible – you can change or cancel any time. There’s no credit check, no commitments and it's all contract-free. Take advantage of unlimited texts and minutes, the perks of both O2 Rewards and Priority, free EU Roaming (up to 25GB) and, with our Rolling Plans, even more data. A Pay As You Go SIM Only deal might suit you if your finances aren’t always predictable or you prefer not to be tied to a contract.

Published: 6 May 2024

Terms and exclusions:

EU Roaming:

Your UK data allowance applies in our Europe Zone, subject to 25GB limit if your UK data allowance is over 25GB. Roaming chargeable at £3.50 per GB after 25GB roaming limit. If you use all of your UK data allowance when roaming outside the UK, you need to purchase a data Bolt On. See Roaming terms and conditions.


Get up to 6 months on us depending on eligible tariff you select (“Extra Period”). Up to 6 months Extra Period: Amazon Prime, Audible, Amazon Music Unlimited, Cafeyn, Disney+ and McAfee. You’ll be automatically opted in to a paid monthly subscription after Extra Period: Amazon Prime £8.99, Amazon Music Unlimited £9.99pm, Audible £7.99pm, Cafeyn £7.99pm, McAfee £4.99pm, Disney+ - Standard Plan with Ads £4.99pm, Standard Plan £7.99pm or Premium Plan £10.99pm. Opt out at any time. Offer may be withdrawn at any time. You will not be eligible to select Amazon Prime if you made a qualifying purchase via a Virgin Media sales channel and/or your Eligible Tariff is part of a bundle or service with Virgin Media. Charges applied to O2 bill & are subject to change. Eligibility & redemption: must purchase new eligible tariff direct from O2. Select Extra within 28 days of making qualifying purchase & redeem within 28 days of selecting Extra. You may not be eligible to select Partner if you hold an existing account with Partner. Must set up Partner account & agree to their terms of use. Disney+: cannot benefit from more than one Extra Period. Disney+ content & related artwork © 2021 Disney & related entities. Amazon: Amazon, Amazon Prime, Amazon Music Unlimited & Audible & all related logos are trademarks of, Inc. or its affiliates. General: tariff eligibility criteria applies which includes being a UK resident, 18+. For how to claim & full terms: