08 numbers
0800 Numbers
0800 numbers are UK freephone numbers - free for the caller to dial from any UK landline or mobile, with the business paying for the inbound calls instead. Get an 0800 number that rings natively on your mobile with ONSIM Landline SIM from £10/user/month + VAT. No app, no VoIP, no desk phone.
Are 0800 numbers free to call?
Yes. Calls to 0800 and 0808 numbers are free from all UK landlines and mobiles. That has been an Ofcom rule since 1 July 2015, when the UK Calling changes made freephone genuinely free from mobiles too. Before then, mobile networks could charge for 0800 calls, which caused years of confusion.
There is no catch for the caller: no connection charge, no per-minute rate, nothing deducted from inclusive minutes. If a number starts 0800 or 0808 and you dial it from a UK phone, the call costs you nothing.
So who pays? The business does
Freephone is not free for everyone - the cost of each inbound call is paid by the business that owns the number. That is the trade-off you are making: you remove every barrier to calling you, and in exchange you pick up the inbound call cost.
To be straight about ONSIM pricing: the Landline SIM plan itself starts from £10/user/month + VAT, and on top of that every call you receive on an 0800 number is charged at a pence-per-minute rate. This is different from 01, 02 and 03 numbers on ONSIM, where inbound calls are included in your plan. The exact per-minute rate is confirmed at signup.
For most businesses the maths still works when each inbound call has real value, such as a sales enquiry - but go in with your eyes open: a busy freephone line is a metered cost, not a flat fee. If you want inbound calls included, an 03 number such as 0330 or 0333 is the cheaper way to run a national number.
Why businesses use 0800 numbers
An 0800 number is a signal: calling us costs you nothing. That signal has measurable effects on inbound call volume, which is why freephone remains popular decades after it launched.
More inbound calls
When the call is free, more people call. For sales lines, quote requests and lead generation, an 0800 number removes the last excuse not to pick up the phone, which is exactly what you want when each call could be a new customer.
Instant credibility
0800 is one of the most recognised number ranges in the UK. It says established, national and customer-focused - a business confident enough to pay for its own inbound calls.
National, not local
Like 03 numbers, 0800 numbers are non-geographic. You can serve the whole UK from anywhere without looking tied to one town. If you want a location-specific presence instead, see ONSIM local numbers.
0800 vs other number types
The key question with any business number is who pays for the call. Here is how 0800 compares.
| Number type | Cost to caller | Cost to business | Best for |
|---|---|---|---|
| 0800 / 0808 (freephone) | Free from UK landlines and mobiles | Business pays inbound call costs | Sales lines, customer service, helplines |
| 0330 / 0333 (national rate) | Same as 01/02, covered by bundles | Standard plan pricing | National presence at lower running cost |
| 01 / 02 (local) | Standard local rate, covered by bundles | Standard plan pricing | Location-specific presence (see local numbers) |
| 084x / 087x (service numbers) | Above standard rate | May receive a share of call revenue | Generally avoided for customer-facing lines |
How to get an 0800 number on your mobile
Because 0800 is an 08 number, it is available on ONSIM Landline SIM - the plan that puts a business number natively on a SIM or eSIM in your existing phone. The £5/month Virtual Landline plan covers 01, 02 and 03 numbers only, so for freephone you start at £10/user/month + VAT.
1. Choose or port your 0800 number
Pick a new 0800 number from available stock, or port your existing freephone number to ONSIM. Port-in is included on Landline SIM plans and typically completes in 10 to 14 working days.
2. It rings natively on your mobile
Your 0800 number is assigned to a SIM or eSIM in your phone. Inbound calls ring like any normal call - no divert delays, no app that needs Wi-Fi, no VoIP quality lottery.
3. Call out showing your 0800 number
Outbound calls can display your 0800 number, so callbacks look consistent and customers can return your call for free. A single SIM can carry multiple numbers, so you can mix 0800 with an 01, 02 or 03 number and choose which to show.
Porting an existing 0800 number
Already have an 0800 number your customers know? In most cases it can be ported to ONSIM, subject to your current provider and the status of the number. The port-in fee is included on Landline SIM plans, porting typically completes in 10 to 14 working days, and your number keeps working with your current provider until the port completes, so there is no downtime window to plan around.
Once ported, your established freephone number rings on your mobile via Landline SIM, and you are free of the desk phone or call-centre platform it was previously tied to.
Pricing, plainly
Landline SIM (from £10/user/mo + VAT): includes your 0800 number, unlimited inbound and outbound UK calls under fair use, and native SIM/eSIM delivery on your existing phone. Voicemail, hold and transfer, and pair-with-deskphone are included.
Inbound freephone call rates: the business pays for calls made to an 0800 number, and inbound call rates for freephone numbers are confirmed at signup. No invented figures here - ask and you will get the exact rate before you commit.
0800 number FAQs
Common questions about 0800 and 0808 freephone numbers and how they work.
Get an 0800 number today
Free for your callers, native on your mobile. ONSIM 0800 numbers run on Landline SIM from £10/user/month + VAT - no app, no VoIP, no hardware.