TalkTalk says its mobile deals offer better value for consumers than the new BT Mobile tariffs announced this week.
The broadband provider - which has been offering mobile services to TalkTalk customers for three years - believes its own packages "offer more for less".
As such, it claims the new BT Mobile deals - which offer discounted minutes, texts and mobile broadband data to BT broadband customers - are "too little too late".
TalkTalk's mobile tariffs, which can be combined with broadband, phone and TV services, are available from £3.75 per month.
They offer built-in savings features such as free calls between family members linked to the home account.
All 24-month plans come with a free smartphone or tablet, plus the Talk2Go calling app - which allows customers to use inclusive landline minutes on their mobile.
Back in December 2014, TalkTalk added a free SIM to its Plus TV package at no extra cost, enabling subscribers to take advantage of 100 minutes, 250 texts and 200MB of data each month.
This is in addition to up to 17Mb broadband, unlimited data, anytime calls and YouView-based TalkTalk TV.
As of March 2015, around 400,000 TalkTalk homes are taking advantage of the company's mobile deals.
Tristia Harrison of TalkTalk said the broadband provider's mission is to make Britain better off.
"That’s why TalkTalk homes make significant savings compared to other providers, while also getting more for their money," she stated.
"We offer better-value tariffs with a great range of handsets."
Ms Harrison claimed that the rapid growth of TalkTalk's mobile base is "proof that more and more homes are reaping the benefits of Britain's best value quad-play services".