Sky Mobile customers who are out of contract are to see their monthly bills rise from Friday ahead of across-the-board increases by other providers from next month.
Out-of-contract Sky customers will see their monthly bills rise by £1.50 a month, which adds up to an £18 a year.
This will come into force from February 14 for pay-monthly and Sim-only customers.
Those who are still within their contract will not see any price change.
The cost of sending an international text message outside Europe will rise by 20p to 95p.
According to the latest data from industry regulator Ofcom, 37% of all pay-monthly mobile customers are out of contract.
Given that Sky Mobile has approximately three million customers, it is estimated that up to one million could see their bills increase.
However, customers who are still within their contract term will not experience any change in their bills.
Customers who are unsure about the status of their contract can text ‘INFO’ and their date of birth in the format DDMMYY to 85075. The provider should then message back straight away to clarify, and how much they will charge in exit fees for leaving.
“It might also be worth considering buying a handset and getting a separate Sim-only plan — Ofcom estimates that on average it’s 23% cheaper than getting a packaged contract. You could even purchase the phone with a 0% credit card, allowing you to spread payments for up to 22 months without paying any interest.”
A Sky Mobile spokesman said: “We always aim to provide an outstanding service alongside some of the best value plans on the market.
“To ensure we can continue to invest in our services and deliver a great experience, the majority of our out of contract customers will see their monthly bill increase by £1.50 in February.”
It comes after inflation-linked mid-contract price rises on phones, pay-TV and broadband were banned by Ofcom, which does not affect Sky, but will affect other broadband customers and mobile users.
Most other mobile networks implement their mid-contract price increases around April 1, making Sky Mobile an exception.
Sky Mobile has traditionally issued its price rises in fixed amounts of pounds and pence, unlike other networks that tie their increases to inflation.
However, as of January 17, all telecoms firms are required by Ofcom to display mid-contract price increases in pounds and pence.