Sky Mobile customers who are out of contract will see the price of their phone bill rise by an average of 9% in a few weeks' time.
“The majority” of its tariffs will increase by £1 a month, with the price rise kicking in from February 14.
Roughly 1.3million customers will see their price go up as a result and Sky says is writing to anyone who will be affected.
The first payments following the price increase will be taken on February 17.
This means if your payment date is before February 17, the increase will show on your next bill.
If you’re still in contract, the price you pay won’t change.
This is because Sky has a promise not to bring in mid-contract price rises for mobile customers.
A Sky Mobile spokesperson said: "This is not a decision we have taken lightly.
"We try to provide our customers with as much value as possible which is why our data plans have not increased in price for five years.
"However due to increased cost pressures the majority of our mobile tariffs are increasing by £1, with the average percentage increase being below levels of inflation."
How to save money on your mobile bill
If you're not happy with the price rise, there are options available.
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.
Once you've found all the best deals available to you, you can either switch to another provider - or try and haggle down Sky.
When haggling, explain the better deals you've seen elsewhere then ask if the company can match or beat that price.
Always be polite when trying to negotiate a better deal.
As well as lowering your mobile bill, you should also compare and haggle down your broadband bill before March.
Many telecom firms are set to hike bills by the rate of Consumer Price Index (CPI) inflation or Retail Price Index (RPI) inflation, plus roughly another 4% on top.
