TalkTalk will hike prices for 40,000 customers from 1 August, with some broadband bills rising by as much as £21 a year.
Some pay monthly mobile phone customers will be even harder hit, with bills rising by up by £30 a year.
The Telecoms giant is in the process of contacting those affected by the increase by letter or email.
People who have signed up or renewed their broadband with TalkTalk since October last year will be on a fixed price plan and so won’t be affected by the price rises.
There will also be increases to call rates for telephone customers.
Customers will pay 13.5p per minute (up from 12.5p per minute) for calls to UK landlines and mobiles.
Call connection charges are going up from 18p to 20p per call, while premium call charges will rise from 7.5p to 10.5p per minute.
A “large proportion” of customers will be unaffected by the call increases as they have all-inclusive packages.
Announcing the changes, a TalkTalk spokesperson said:
"We’ve been investing millions in improving our unlimited broadband network, making our TV service faster and simpler to use, and introducing industry-leading security services and calling features which we provide as standard.
"If you're on one of our Fixed Price Plans we can guarantee your broadband price will stay the same for the length of your contract. If your package has a boost with inclusive calls these charges may not affect you."
How to beat the hikes
If you want to move away from TalkTalk and you’re not within the minimum term of your contract, you can leave without paying an exit fee.
Head over to broadbandchoices.co.uk or Recombu to find the best broadband and mobile deals for you.
If you’re on a Simply and Essential broadband plan or locked in a mobile contract, Ofcom says you have the right to cancel fee-free.
Just tell TalkTalk within 30 days of receiving your letter or email detailing the price changes. If you don’t, you’ll need to pay a termination fee.
Those who want to stay with the provider have the option of calling up and haggling for a better deal. Read How to haggle and save a fortune to find out more.
Alternatively, you can have a look at how to cut your Sky bill and how to cut your BT bill.
Compare broadband offers with broadbandchoices.co.uk