Elyse Betters Picaro / ZDNET Follow ZDNET: Add us as a preferred source on Google. ZDNET's key takeaways Verizon promises to beat the price of your AT&T or T-Mobile plan. The deal works with comparable plans among the three major carriers. You'll have to present your current bill or account details to qualify. Looking to trim the cost of your mobile phone plan? If you're an AT&T or T-Mobile subscriber, you could save money by jumping ship to Verizon. At least, that's the promise. In a new "Switch to Verizon" promo, the carrier is inviting customers from its two major rivals to present their latest mobile phone bill information, either in-store or online. In response, Verizon claims that it will find a comparable plan at a cheaper price. If you want to try this in-store, the website will point you to nearby locations. If you go the online route, Verizon will ask for all the details of your current plan and then see if it can undercut the price. Also: I compared 5G network signals of Verizon, T-Mobile, and AT&T at a baseball stadium - here's the verdict The promo page also displays an interactive chart that purports to show you the difference in price among plans from Verizon, AT&T, and T-Mobile. You can set the number of lines, anywhere from one to four. You can also check out different perks such as a Disney bundle, Netflix and HBO Max, Apple One, YouTube Premium, family monitoring, and international calling. With each variation, Verizon comes up the cheapest. But to find out if that holds up, you'd have to present your latest bill or the details on your account to Verizon, which then determines the true cost of a comparable plan. Below the chart are further details that break down each feature and perk across the three carriers. To kick off the process, you must share the part of your current bill that shows your name, address, phone numbers, bill date, current plan details, device payments, and price. You can use a physical, digital, or PDF version of your bill for this. The bill must be for a postpaid account with T-Mobile or AT&T from within the past 45 days and have the same name as the account that would switch to Verizon. You would also need to ensure that your current phone number is portable to Verizon. A government mandate called Wireless Local Number Portability requires that carriers be able to port a number. Verizon says that most numbers are eligible, though some may not be supported based on geography, service area coverage, technology, or line ownership. Also: The fastest US mobile carriers and ISPs, ranked If you move forward with the actual transfer, you'd have to provide your current phone number, the account number of your previous provider, an account or security code, and another number where you can be reached during the process. On Verizon's end, the current postpaid plans to which you might switch include Unlimited Ultimate, Unlimited Plus, and Unlimited Welcome. The cost of your new plan is guaranteed for three years. However, that guarantee doesn't include the usual taxes and fees, which have a habit of increasing over time. Get the morning's top stories in your inbox each day with our Tech Today newsletter. Based on a Reddit thread spotted by The Street, Verizon is reportedly using AI to compare similar mobile plans among the three major US carriers. One commenter said that Verizon's AI tool looks for any discounts that can be applied to your current bill through AT&T or T-Mobile and then applies a similar discount only if Verizon's pricing isn't already lower. If this doesn't work as expected, you might need to contact Verizon customer support to explore your options.