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7 Mistakes To Avoid When Switching Cell Phone Carriers

Avoid making these seven mistakes to ensure switching cell phone carriers goes as smoothly as possible.
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I have switched my cell phone carrier four times in the past three years.

My phone number has gone from Mint Mobile to T-Mobile to MobileX to Boost Infinite and is now at US Mobile.

Here are seven mistakes to avoid when you switch cell phone carriers:

  1. Cancelling your old service too early
  2. Not getting your phone unlocked before you leave
  3. Not entering the correct account number or transfer PIN
  4. Waiting until the weekend to switch carriers
  5. Having Number Lock turned on
  6. Removing your old SIM card too early
  7. Not taking advantage of any new customer promotions or referral codes
Arrow pointing from phone with Verizon's $80 Unlimited Plus plan displayed on screen to a phone with Visible's $25 Unlimited Base plan displayed on screen

1. Cancelling Your Old Service Too Early

Some people think that when you want to switch to a new cell phone carrier, you first need to cancel service with your current carrier.

You would not want to be billed for service from both your old carrier and your new carrier at the same time, right?

It turns out, this is a mistake you need to avoid!

Cancelling service with your old carrier too early may prevent you from transferring your precious phone number from the last 20 years to your new carrier.

Instead, what you want to do is keep your current service active.

This will ensure you will be able to transfer your phone number successfully and not run in to problems.

But what about getting double-billed?

It turns out that going through the process of transferring your phone number from one carrier to another will automatically cancel your service with your old carrier.

So you don’t need to worry about paying for two plans at the same time!

2. Not Getting Your Phone Unlocked Before You Leave

There is no worse feeling than signing up for a new carrier and then checking your phone to see a popup that reads, “SIM not compatible.”


How could this be? Your new carrier SAID your phone was compatible. You entered the IMEI in the compatibility checker and everything! What could be happening??

Odds are, your phone may still locked to your previous carrier.

A locked phone is a phone that is tied to a carrier or contract.

Almost all phones you purchase directly from a carrier are locked to that carrier. That means your phone won’t work with your new carrier, even if it has the correct hardware to be compatible with your new carrier. The good news is that you can request that your current carrier unlock your phone.

An unlocked phone is one that isn’t tied to any carrier or contract and will work on any cell phone plan.

Your phone is eligible to be unlocked typically once it is paid off in full and you have been a customer with the carrier for a certain period of time.

The unlocking process is usually pretty easy. Your phone will either be unlocked automatically when the unlock criteria are met, you can submit a form online, or you can quickly chat with support to submit a request.

However, the essential thing is you get your phone unlocked before you leave your current carrier.


Because the moment you leave your current carrier, they feel no obligation to help you out and unlock your phone for you.

There are horror stores on Reddit of people leaving their old carrier without getting their phones unlocked first, and then being stuck with locked phones because their old carrier won’t honor their unlock request.

It’s a disaster.

If you don’t get your phone unlocked before you leave, then you’ll be stuck having to buy all new phones.

3. Not Entering Your Account Number and Transfer PIN Correctly

When you transfer your phone number from one carrier to another, you will be asked to provide your account number and PIN to your new carrier.

Your new carrier submits this information to your old carrier to authenticate the number transfer.

It is essential that this information is correct.

A single-digit typo in the account number or PIN can cause the transfer to fail, delays in your activation, numerous calls to customer support, and a low-grade migraine.

I want you to avoid that!

Double-check to make sure you write down the information correctly, and triple-check what entered in the fields with your new carrier matches what you have written down. Better yet, try to copy and paste as much as possible, as this reduces the likelihood of an accidental error!

Also, make sure you grab the correct number transfer PIN.

Your number transfer PIN is different from your account PIN. Your account PIN is usually a four to six digit number used to authenticate your account when you contact support. Meanwhile, your number transfer PIN is exclusively used for transferring your phone number.

You do not set your number transfer PIN.

It is randomly generated. Usually a transfer PIN is only valid for one week after it is created. So make sure you start the number transfer process within that timeframe.

The good news is if all your information is correct, then your phone number should transfer seamlessly to your new carrier in just a few minutes!

That said, sometimes there can be other delays.

Most phone number transfers take between 2 minutes and 15 minutes. However, sometimes a number transfer can take up to 48 hours, even with all your information entered correctly. That happened to me when I ported my phone number from US Mobile to Mint Mobile in 2017.

That brings us to the next mistake to avoid…

4. Waiting Until the Weekend To Switch Carriers

A lot of people love saving big projects for the weekend.

It makes sense.

You have more time, you are less busy with work, and in general weekends are just great opportunities for bigger projects.

However, not when it comes to switching to a new cell phone carrier.

When you’re switching to a new cell phone carrier, trying to do so on a weekend is a mistake.

Why is it a mistake? Because if something were to go wrong or you needed help during any part of the process, customer service for the carriers hours may be limited on the weekends. Or, wait times could be longer because everyone else was waiting until the weekend to contact support to deal with their phone issues.

Instead, you want to switch cell phone carriers during business hours from Monday to Friday.

Wait, interrupt your work day to switch your cell phone carrier?

Am I crazy?

It may sound absurd to try and switch your cell phone carrier on a Tuesday at 10:24 in the morning, but hear me out. Your phone is valuable to you, especially if you take business calls, speak to clients, and land sales. You want as little downtime as possible.

By switching to a new carrier mid-week during normal business hours, you are guaranteeing that customer support teams from both your old carrier and your new carrier are on standby and ready to help you out.

This means if something does happen, the people who can fix it are available to help.

So switching carriers during business hours I think is one of the best ways to minimize downtime and help you have a smooth experience.

Plus, who goes to an AT&T store on a Tuesday at 10:24am anyway?

5. Having Number Lock Turned On

SIM swapping attacks have been on the rise recently.

A SIM swapping attack is where a bad actor transfers your phone number, without your authorization, to a completely different phone that they are in control of.

They do this so they can get the two factor authentication codes that are sent as texts to your phone and use those to hack into your various accounts, such as your bank accounts or crypto wallets. You can imagine what happens next.

To combat SIM swapping attacks, some carriers launched new security features to help keep your phone number safe and secure.

On July 9th, 2020, Verizon launched Number Lock to help prevent unauthorized port out attempts.

Similarly, T-Mobile launched Account Takeover Protection on March 17th, 2022, as an additional security layer.

These added layers of security are great for keeping your phone number safe by blocking port out attempts.

But that’s the thing! These features block port out attempts!

When you are switching to a new carrier, that is exactly what you are doing—porting your phone number from one carrier to another.

So before you switch, you need to to turn off Number Lock or Account Takeover Protection to make sure your number can transfer successfully.

Don’t be like me and think your number transfer didn’t go through because you entered your 16-digit account number wrong when really it was just a simple setting left turned on.

6. Removing Your Old SIM Card Too Early

When most people switch to a new cell phone carrier, they immediately remove their old SIM card and insert their new SIM card.

Or, if they are on a device with eSIM, they delete their old eSIM profile and install the new eSIM profile from their new carrier.

This may sound silly, but removing your old SIM card too early is a mistake to avoid.

Why is this?

It is because your old SIM card will remain active up until the second your phone number is transferred. Until that moment, you’ll still receive all calls and texts on your old SIM. And your old SIM will have a working cellular data connection.

Removing or deleting your old SIM card too early may leave you without service on your phone. You may also miss any incoming calls and texts.

It is best to leave your current SIM in your phone for as long as possible.

Sure, you may need to pop it out to activate your new SIM card. But if your new SIM card does not activate right away or does not get service, it means your old SIM is still active. You can pop it back into your phone and continue getting service until your new SIM is active.

It is especially helpful to keep your current SIM installed if you have an eSIM.

There is no need to remove it or delete it until you know your new eSIM has been activated successfully.

It’s best to wait until your new service is activated before permanently deleting your old eSIM or throwing out your previous physical SIM card.

7. Not Taking Advantage of New Customer Promotions or Discounts

Almost every single cell phone carrier will offer special promotions for new customers.

You don’t want to miss out on these!

Switching to a cell phone carrier is your own opportunity to take advantage of the best deals that carrier has to offer. And these promotions can easily add up to save you a couple hundred bucks.

Check online forums, this website, Reddit, or other resources to see what the current deals are.

Verizon, AT&T, and T-Mobile also offer exclusive discounts for military veterans, first responders, teachers, nurses, physicians, and other personnel.

Many carriers will also offer great deals on new smartphones to new customers.

Additionally, more and more carriers are starting to have referral programs these days. Consider checking online or asking one of your friends to see if they have a referral code you can use.

Add up the various discounts to get the best deal possible when you switch cell phone carriers.

And with that said, those are the seven mistakes to avoid when switching cell phone carriers. I hope you found this article helpful.

Please share this article with a friend because it helps me out.

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Written by:
Stetson Doggett profile picture
Stetson Doggett

Stetson graduated from Ithaca College in 2019 with a degree in Communication Management and Design. He launched as part a senior project in school. He loves helping people find great, affordable cell phone plans that meet their needs. When he’s not reviewing cell phone plans on his YouTube channel or website, Stetson is out hiking in the crisp Colorado air, playing board games with friends, or competing in an epic game of pickleball.

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