Millions of O2 and Virgin Mobile customers will be hit with price hikes of up to 17.3%.
The increase will apply to SIM-only deals, or just the airtime part of your contract if you're a Refresh customer - so what you pay for minutes, texts and data.
This is separate to what you pay for your handset - the price of this won’t be going up.
Customers who are mid-contract will see their airtime bill increase from April.
Virgin Media O2 uses the Retail Price Index (RPI) measure of inflation for January, plus 3.9%, to determine price rises for the following April.
RPI for January was 13.4% which means airtime bills will go up by 17.3%.
Virgin Media O2 told The Mirror that the average customer will technically see a smaller rise of 10% overall, due to how it splits bills into airtime and device plans.
How much extra you could pay depends on what you’re currently paying.
As an example, if someone had an iPhone 14 Pro costing £53.98 per month for 36 months, they would pay £4.15 more each month.
This is because their deal is made up of £29.98 per month for the device and £24 for their airtime - this would mean they pay 7.7% extra.
The 17.3% on airtime bills applies to customers who took out a deal or upgraded from March 25, 2021.
Anyone who took out a new deal or upgraded before this time will see their bill go up in line with just RPI of 13.4%.
Pay-as-you-go users are unaffected by the price rises.
A Virgin Media O2 spokesperson said: “We know that price increases are never welcome but, unlike other providers, we freeze the cost of device repayments and are only changing our airtime prices, meaning average bills will go up by an effective 10.0% or less than 10 pence per day.
“This is below inflation and reflects the fantastic value we provide for connectivity that is used almost constantly.
“These changes occur as our own business costs rise and we invest heavily in our mobile network to keep pace with ever increasing usage, rollout new technologies like 5G and deliver valuable services that matter to our customers – whether that’s flexible plans, inclusive EU roaming or access to exclusive events and savings through Priority.”
The news from Virgin Media O2 comes after Ofcom confirmed it was launching an investigation inflation-linked price rises on phone and broadband contracts.
The broadcasting watchdog is looking into whether mid-contract prices give customers enough certainty about what they can expect to pay.
Other major providers including BT, EE and Sky have already announced price rises of up to 14.4% for their mobile customers.
How to cut the cost of your broadband and mobile bill
If your mobile bill is about to get more expensive, you might be able to cut costs.
If you're out of contract, you're free to leave and go elsewhere - or maybe you want to haggle down your current provider.
There is also no harm in trying to haggle if you're still in contract.
The first thing you should do, is compare prices elsewhere to see what other deals are available.
You'll normally find SIM-only plans are the cheapest.
You can compare prices by using comparison websites such as MoneySupermarket and Uswitch.
Take a look at how many minutes, texts and how much data you currently use, so you can find similar plans that suit your needs.
You may find you're actually paying too much right now for allowances that you're not using.
When haggling, explain the better deals you've seen elsewhere then ask if the company can match or beat that price.
