Comparing Mozillion
vs O2
If you're looking to switch provider, choosing between Mozillion and O2 can depend on what matters most to you — whether that's flexibility, pricing, international usage, or overall network experience.
How the networks compare
Both Mozillion and O2 provide access to reliable UK mobile coverage, but there are some differences in how our services and O2’s are delivered.
O2 Network Coverage and Reliability
O2 operates its own UK mobile network, with widespread 4G coverage and a growing 5G footprint. It's one of the UK's longest-established providers, known for strong urban coverage and reliable indoor signal.
Independent testing from organisations such as RootMetrics shows O2 delivers consistent performance, though it typically trails networks like EE on peak speeds.
- Wide national 4G coverage
- Expanding 5G availability
- Strong indoor and urban reliability
- Consistent, though not fastest, performance
Mozillion Network Coverage and Reliability
Mozillion operates on its own network powered by the UK's Best Network, recognised for strong performance in independent testing.
Mozillion offers features such as uncapped 5G speeds, no mid-contract price rises, and nationwide coverage.
- SIM plans use the UK's Best Network
- Performance depends entirely on the underlying carrier
- Access to nationwide 4G and uncapped 5G where available
- Flexible marketplace model with transparent pricing
Staying connected abroad
The way each provider handles roaming and international features can significantly shape the overall user experience, especially for those who need functionality beyond standard mobile services.
O2 Roaming and Travel Coverage
O2 offers roaming across a range of destinations, with EU roaming included on its plans. Customers can use their UK allowance for calls, texts, and data in 40+ European destinations at no extra cost, subject to a fair usage limit (typically up to 25GB).
Outside Europe, roaming is available but usually chargeable, either through daily rates, standard roaming charges, or bolt-ons such as O2 Travel depending on the destination and tariff.
- EU roaming included across O2 plans (use of UK allowance)
- Fair usage limit applies (typically up to 25GB in Europe)
- Roaming outside Europe is usually chargeable
- Availability and pricing depend on plan and destination
Mozillion Roaming and Travel Coverage
Mozillion offers roaming on its mobile plans in 41 EU destinations, allowing customers to use their UK allowance while travelling in Europe at no extra cost.
Roaming outside the EU is available depending on the destination and is subject to charges, with usage and fair use policies.
Mozillion also provides a Travel eSIM for data use in over 200+ countries, offering a convenient way to stay connected when travelling abroad.
- EU roaming included in 41 destinations on eligible plans
- Roaming outside the EU is chargeable and destination-dependent
- Fair usage and network rules apply
- Travel eSIM available for data use in 200+ countries worldwide
Roam the world for less
You can save up to 90% on roaming charges with Mozillion's Travel eSIM — available in over 200 countries worldwide.
What else do you get?
We also look at the features and added perks each provider offers, as these can significantly shape the overall user experience.
O2 Features and Added Perks
O2 focuses on core mobile connectivity, supported by a range of additional benefits through its Priority rewards platform. This includes early access to tickets for thousands of events, along with exclusive offers, discounts, and experiences from a variety of partner brands.
While its primary service is mobile connectivity, these added features provide extra value beyond standard network services.
- Core focus on mobile connectivity
- Priority ticket access and presales for events
- Exclusive offers and partner discounts
- Added value through its rewards platform
Mozillion Features and Added Perks
Mozillion provides a wallet system that allows customers to add credit for eligible services, managed directly through the customer account.
Mozillion also includes Kill Your Bill, a feature that allows customers to reduce their monthly bill by purchasing eGift Cards through the Mozillion app. Rewards earned from these purchases are applied directly to the customer's bill.
- Wallet system used for adding credit to eligible services
- Kill Your Bill reduces monthly bills via eGift Card rewards
- Account dashboard used for managing usage and account settings
- Real-time visibility of data, billing, and usage
Pick your plan, start killing it.
All Kill Your Bill SIM only plans include unlimited calls & texts, EU roaming, and uncapped 5G speeds on the UK's Best Network 2025.
10GB
£6 a month
24 month plan
- Kill Your Bill rewards
- Unlimited calls & texts
- Uncapped 5G speeds
- Free EU roaming
- No mid-contract price rises
30GB
£8 a month
24 month plan
- Kill Your Bill rewards
- Unlimited calls & texts
- Uncapped 5G speeds
- Free EU roaming
- No mid-contract price rises
100GB
£12 a month
24 month plan
- Kill Your Bill rewards
- Unlimited calls & texts
- Uncapped 5G speeds
- Free EU roaming
- No mid-contract price rises
Unlimited
£20 a month
24 month plan
- Kill Your Bill rewards
- Unlimited calls & texts
- Uncapped 5G speeds
- Free EU roaming
- No mid-contract price rises
How do you get set up?
The type of SIM you choose can influence how quickly you get set up and how easily you can switch between devices or plans.
O2 offers both physical SIM cards and eSIMs, giving customers flexibility in how they connect. Physical SIMs are widely available, while eSIM is supported on selected plans and compatible devices.
- Physical SIM widely available; eSIM supported on selected plans
- eSIM allows quick digital setup and activation
- Switching supported on compatible devices
- Availability depends on device and plan
Mozillion offers both physical SIM cards and eSIMs across all its mobile plans, giving customers flexibility in how they connect.
- Physical SIM and eSIM available across all plans
- eSIM allows digital activation and setup
- Physical SIM available as standard option
- Availability depends on device compatibility
Compare both SIM-only deals
Compare both SIM-only deals available right now so you can make an informed choice!
| How they compare | Mozillion | O2 |
|---|---|---|
| Monthly cost | £20 | £34 |
| Data | Unlimited | Unlimited |
| Mins & Texts | Unlimited | Unlimited |
| Uncapped Speeds | ✓ | ✗ |
| EU Roaming | ✓ | ✓ |
| Credit Checks | ✗ | ✓ |
| Network | Mozillion | O2 |
| Trustpilot Score | 4.3 | 1.2 |
Every Mozillion plan includes:
• The UK's Best Network • Fastest uncapped 5G speeds • Free EU roaming in 41 countries • No contract or credit check • No mid-contract price rises
Reviews from Mozillion customers that switched from O2
Having Been With O2 For Years
"Having been with O2 for years a friend told me about Mozillion. So I looked into it and thought it was better than O2 so I changed."
Read more →One Third The Monthly O2 Price
"50% more GB, ONE THIRD THE MONTHLY O2 PRICE. Trouble free change. Better connectivity."
Read more →New SIMs Same Number
"The two SIMs arrived in the morning and our numbers were changed a few hours later. Getting a better coverage than I was with O2."
Read more →