Compare O2 SIM Only Deals 2025 UK

If you are looking for the best SIM only deals in the UK, you are at the right place. Whether you want flexibility, value, or exclusive perks, O2 offers a wide range of SIM-only plans. You can tailor them to your needs, and they are suitable for every type of mobile user. Here we have compared and evaluated the latest offers related to O2 SIM only deals, so you can discover why O2 remains a top choice for SIM only contracts in 2025.

Why Choose O2 SIM Only Deals?

O2 delivers extensive network coverage, with up to 99% 4G coverage across the UK, and continues to expand its 5G network as well. This ensures fast and reliable connectivity in most locations.

O2 SIM Only Deals at a Glance

Prices are accurate as of April 2025. All plans typically include unlimited minutes and texts. Offers can vary.

Key Features and Perks of O2 SIM Only Plans

• Flexible Plans: Choose from a variety of contract lengths, including 12-month, 24-month, and flexible Pay As You Go options.

• Varied Data Allowances: Plans offer data allowances ranging from smaller amounts up to Unlimited data, with most standard plans including unlimited calls and texts.

• Inclusive EU Roaming: O2 is one of the major UK networks that still offers inclusive EU roaming on many plans, allowing you to use your UK allowance in Europe (a fair usage policy, typically up to 25GB per month, applies).

• O2 Priority: Enjoy exclusive access to O2 Priority, which offers early ticket access to gigs, discounts at high-street retailers, and regular freebies.

• O2 Rewards: Pay As You Go customers can benefit from O2 Rewards, giving up to 10% back on top-ups every three months.

• O2 Wi-Fi Hotspots: Access over 15,000 O2 Wi-Fi hotspots nationwide, plus Wi-Fi calling for better indoor coverage.

• Data Rollover: Unused data can be rolled over to the next month on selected plans, ensuring you get the most out of your allowance.

• Streaming Trials: Many O2 SIM-only deals come with free trial subscriptions to popular streaming services like Disney+, Apple Music, or Prime Video.

• International Roaming: Beyond the EU, O2 offers various international roaming options and bolt-ons.

• Caters to Heavy Users: With large data allowances and unlimited options, O2 caters well to streamers, gamers, and social media enthusiasts.

• Credit Checks: O2 runs credit checks for pay monthly contracts, but Pay As You Go SIMs are available without a credit check.

Who Should Get an O2 SIM Only Deal?

If you already own a phone and you are happy with it, switching to a SIM-only deal can save you money compared to a traditional phone contract.

How to Choose the Best O2 SIM Only Plan

First, assess your data usage. Average users might use around 5-19GB per month, but heavy streamers, gamers, and remote workers may need 50GB, 100GB, or even unlimited data. Consider plans that include perks like streaming trials, O2 Priority, and data rollover for added value. 12- and 24-month contracts typically offer better value, while Pay As You Go suits those needing maximum flexibility.

How to Switch to O2 and Keep Your Number

Switching to O2 is simple. As a first step, request a PAC (Porting Authorisation Code) from your current provider by texting ‘PAC’ to 65075. As a second step, provide this code to O2 when you sign up for your new plan. Your number will then usually be transferred within one working day.

Frequently Asked Questions (FAQ)

What is the cheapest O2 SIM-only deal?

O2’s cheapest SIM-only plan typically starts at around £8 per month for a good allowance of 5G data (e.g., 32GB), unlimited calls, and texts, usually on a 12-month contract. Prices and allowances vary, so always check current offers.

Does O2 offer unlimited data SIMs?

Yes, O2 offers unlimited data SIM-only plans, which are perfect for heavy streamers and gamers. Fair usage policies apply, especially concerning tethering and roaming.

Can I use my O2 SIM abroad?

On many 12-24 month contracts, O2 includes EU roaming, allowing you to use your UK allowance in European destinations at no extra cost, up to a fair usage limit (often 25GB per month). For destinations outside the EU, O2 offers travel bolt-ons for a daily fee or other specific international roaming packages.

Is 5G included in O2 SIM-only deals?

Yes, all new O2 SIMs are 5G-ready at no extra cost. You will need a 5G-compatible phone and to be in a 5G coverage area to access 5G speeds.

Can I keep my existing number when switching to O2?
Absolutely. Simply request your PAC code from your current mobile provider (text 'PAC' to 65075) and give it to O2 when you sign up. They will handle the transfer.

Are O2 SIM cards free?

Yes, O2 does not typically charge for the SIM card itself. You only pay for your chosen monthly plan or Pay As You Go credit.

Do O2 SIM-only deals include perks?

Yes, most O2 plans come with access to O2 Priority (for early ticket access, discounts, and freebies), potential streaming trials, access to O2 Wi-Fi hotspots, and O2 Rewards for Pay As You Go customers.

Ready to find your perfect O2 SIM only deal?

Compare the latest offers and enjoy reliable coverage, exclusive perks, and flexible plans with O2 today.