Fiver vs O2
Fiver vs an O2 Data Bolt On
This is the comparison that made us build Fiver. O2's Data Bolt Ons are priced per gigabyte and they are not cheap — £12.50 for a single gigabyte, £24.99 for 8GB. If you've got a few days to go and you use your phone normally, a Fiver costs less than O2's smallest useful bolt-on and doesn't leave you rationing.
Get 5GB for £5What O2 Data Bolt On actually sells
O2 Data Bolt Ons are a one-off payment for a fixed amount of data valid for just over 30 days: 100MB £5.50, 500MB £8.50, 1GB £12.50, 2GB £15.50, 4GB £18.99, 8GB £24.99, 12GB £32.50. Added through My O2.
What running out costs
Fiver is one price: £5.00 for 5GB, however long you're short for. Their prices were read off their own site on 2 August 2026.
| If you're short for | Fiver | O2 Data Bolt On |
|---|---|---|
| 1 day | £5.00 | £12.50 for 1GB — the smallest bolt-on that covers a normal day |
| 3 days | £5.00 | £15.50 for 2GB, or £18.99 for 4GB |
| 5 days | £5.00 | £18.99 for 4GB |
| 7 days | £5.00 | £24.99 for 8GB |
Side by side
| Fiver | O2 Data Bolt On | |
|---|---|---|
| What you're buying | Days — 1GB of full-speed data refreshed every 24 hours | A fixed lump of gigabytes to eke out |
| What happens at the end | It stops by itself | Bolt On expires after ~30 days |
| Cost of a light week | See the table above | £18.99–£24.99 |
| Do you need to be an O2 customer? | No — any network, any unlocked eSIM phone | Yes |
| Setup | eSIM, live in a couple of minutes | Instant in My O2 |
| Keeps your number | Yes — data only, sits alongside your normal SIM | Yes — it's your existing line |
When O2 Data Bolt On is the better buy
- You genuinely only need a few hundred megabytes to get through. £5.50 for 100MB is poor value per gigabyte but it's a small amount of money.
- Your phone doesn't do eSIM, or you'd rather not touch your settings at all.
- You want the data to sit on your existing O2 number with nothing else to manage.
5GB
£5
Expires After 30 days
eSIM Delivered Instantly
Common questions
- Why is a Fiver cheaper than an O2 bolt-on?
- Because we're not selling you gigabytes at a markup. We buy wholesale UK data by the day and sell you the days you need. O2's bolt-ons are priced to make running out expensive.
- Does Fiver work if I'm on O2?
- Yes. It's a separate data-only eSIM. Your O2 SIM keeps your number, calls and texts; your phone uses Fiver for data until your allowance resets.
- How much data do I get?
- 1GB at full speed every 24 hours, which covers normal use — maps, messaging, socials, music. After that daily gigabyte it slows down until the next day rather than stopping.
- Will O2 charge me anything for using Fiver?
- No. You're not changing anything on your O2 account. Nothing is added, nothing is cancelled.
Where these numbers came from
Prices checked 2 August 2026. Other networks change their prices without telling us — always check theirs before you buy.