Sky Mobile customers who are out of contract will see their monthly bills increase by £1.50, adding £18 extra annually, starting this Friday.
The price hike precedes widespread increases planned by other mobile providers from March.
The change, effective from 14 February, applies to pay monthly and SIM-only customers.
Those currently within their contract period will be unaffected by the price adjustment.
Sky Mobile is also hiking the cost of calls to the EU and EEA by 4p to 25p per minute, while calls to the rest of the world will be increasing by £1 to £3.50 per minute.
The cost of sending an international text message outside of Europe will rise by 20p to 95p.
According to the latest data from Ofcom, 37 per cent 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 customers could see their bills increase.
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.
Totally Money chief executive Alastair Douglas said: “There’s a lot of deals out there, with varying contract lengths, voucher incentives, and offers. Just shop around to see what each provider is offering, and double check the network coverage before signing up.
“It might also be worth considering buying a handset and getting a separate Sim only plan — Ofgem estimates that on average it’s 23 per cent cheaper than getting a packaged contract. You could even purchase the phone with a 0 per cent credit card, allowing you to spread payments for up to 22 months without paying any interest.”
A Sky Mobile spokesperson 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 was banned by Ofcom, which doesn’t affect Sky – but will impact other broadband customers and mobile users.
Most other mobile networks implement their mid-contract price increases around 1 April, making Sky Mobile an exception.
Sky Mobile has traditionally issued its price hikes in fixed amounts of pounds and pence, unlike other networks that tie their increases to inflation.
However, as of 17 January, all telecom firms are required by regulator Ofcom to display mid-contract price increases in pounds and pence.
Under the new rules, the maximum permissible price rises will be capped at between £1 and £3 per month.
