If you don't have access to your phone, there are a few options for confirming your identity. The caveat is that most of them must be set up ahead of time.
The issue is that giving Google your new phone number necessitates you being logged in, which you are unable to do since the verification is sent to your old phone number. It's a never-ending cycle.
I'm afraid I have to inform you that you may not be able to get in based on a few things.
Alternative verification methods that may be used
As part of two-factor authentication
use a hardware security key that you set up.
Use a one-time security code given by another device that has been signed in.
On a signed-in phone or tablet, confirm.
On a signed-in phone or tablet (even if it's offline), get a security code.
Use the Google Authenticator app to get a code.
A verification code will be sent to the recovery email address.
A verification code will be sent to your phone.
One of your pre-saved 8-digit backup codes should be entered.
Google Account Recovery is a good option.
Prepration is essential.
Before this scenario occurs, Google will require anything that has been set up, logged in, or configured. In most cases, this entails adding your phone number and keeping it up to current.
Of course, if you've misplaced your phone or changed your phone number without updating your account information, this won't work.
Fortunately, Google provides a plethora of other methods for confirming your identity.
Google's two-factor authentication. To see a bigger version of this picture, please click here. (Image courtesy of askleo.com)
Important: You may not have access to all of these choices in all circumstances (and there may even be others). Which Google makes accessible is unknown, and it may differ based on your account's attributes or whether you're using the “forgot my password” or “lost my two-factor device” paths.
Several of these options need setup before they may be used. They won't be displayed if you haven't set them for your account.
Even if you don't have two-factor activated, Google's security may need this extra level of authentication from time to time. This is also known as two-factor authentication.
Let's have a look at the possibilities.
I am serious when I say that preparedness is essential. This is why: A One-Step Method to Permanently Lose Your Account
Options for account verification
Make use of the Security Key
All you have to do with a hardware security key like a YubiKey is plug it into a USB port and push a button to prove you are who you say you are.
Only if you've already configured the YubiKey with your account and have it with you will this function. Despite the fact that I've allocated a YubiKey to my account, the most frequent situation I encounter is not having it with me.
You'll be given a one-time security code.
You can check in to your account on one device using a hardware security key, and then use that device to obtain a code to sign in to another.
This scenario implies you can't sign in with your security key on the device you're using. Maybe the USB ports are damaged, or maybe you forgot your key at home. You may use your ability to sign in one location as a means to verify the other by utilizing a separate device (and possibly a trusted family member at home).
On your phone or tablet, double-check.
If you are presently logged in to Google on a mobile device or tablet, Google may send you a message asking you to confirm your sign in on that device.
This, of course, only works if you're logged in on another device and can reply to the confirmation question.
To obtain a security code, use your phone or tablet (even if it's offline).
This one took me by surprise. I believe this is just for Android devices, however if you're logged into the same account on both, you'll be given instructions on how to get a log-in token from one of them.
Get a security code from your phone using these instructions. To see a bigger version of this picture, please click here. (Image courtesy of askleo.com)
Following that, your smartphone displays the codes you may use to verify your identity.
Google's security codes for mobile devices. To see a bigger version of this picture, please click here. (Image courtesy of askleo.com)
It may be a lifesaver, particularly while traveling, because this works even if the mobile device is not linked to the internet.
Use the Google Authenticator app to get a verification code.
This also doesn't need any mobile device connection, but it does necessitate setting up two-factor authentication using the Google Authenticator app beforehand. Authy and other similar applications also function.
You just enter in the presently displayed code for your account on the device running the authenticator app (which may even be the PC on which you're trying to sign in if it's running the desktop version of Authy).
Receive a verification code through email.
A code will be sent to one of your recovery email addresses by Google. Your ability to give that code verifies that you are who you claim you are — or at the very least, that you set up the recovery email addresses — and that you should be granted access to the account.
Email addresses aren't usually included in the list of choices (for example, they're not shown above).
Options for recovering your Google account through email. To see a bigger version of this picture, please click here. (Image courtesy of askleo.com)
It's worth noting that your account may have several recovery email addresses connected with it. Four are shown in this example. You may have the code delivered to any of the others if you lose access to one.
Receive a verification code through text message.
This is the issue that has brought us to this point. Google will send a code to your registered mobile phone number.
It's worth noting that your account may have several phone numbers connected with it. You may have the code transmitted to the other if you lose access to one.
One of your 8-digit backup codes must be entered.
With two-factor authentication enabled, you may have Google generate and display a set of backup codes for you to use in an emergency at any time you're logged in to your account.
Backup codes for Google accounts. To see a bigger version of this picture, please click here. (Image courtesy of askleo.com)
Each one may be used once – either in place of your second factor or when you need to provide Google more security assurance that you are who you claim you are.
If you use two-factor authentication, I highly advise you to get and save backup codes in a secure location.
If the added protection provided by two-factor authentication isn't enough to persuade you, it's almost worth turning it on just to have these codes on hand in case you need them.
This procedure, according to Google, may take several days. They don't mention that it may not work.
Account recovery on Google. To see a bigger version of this picture, please click here. (Image courtesy of askleo.com)
The procedure encourages you to use some of the alternatives we've previously covered as quicker methods to access your account.
If they don't work, Google will ask you a series of questions before responding. Answer the questions as clearly as thoroughly as you possibly can.
If you've given enough information, you'll ultimately be able to log into your account and reset your password.
You're out of luck if you haven't supplied Google with enough information to verify you're the legitimate account owner. This is a frequent occurrence.
What frustrates people in this situation is that Google never specifies what constitutes “enough.” This is done on purpose to keep malevolent hackers out of the system. That's why I stress the need of being thorough, clear, and comprehensive while answering the questions.
If everything goes wrong,
If none of the Google confirmation methods work for you…
if you haven't set up your account's alternative and recovery details…
If the account recovery procedure described in the previous step doesn't work…
If that's the case, I'm afraid there's no way to get back into your account. It's no longer your account for all intents and purposes.
This is why I stress the need of creating account recovery information and activating two-factor authentication before you need it, so you don't end yourself in this position.
If I lose my phone, how can I verify my Gmail account?
If you lose your phone, you can log in to your Gmail account by having your mobile carrier move (or “port”) your phone number to a new device so you can receive verification codes there, or by using an alternate method of recovery you set up beforehand, such as an alternate email address you have access to. If none of those choices are available, click the “Forgot password?” link and carefully follow the steps to try to regain account access.
So in this way and method you can verify your Gmail Account without phone. Hope you got it completely.