Google 2 step verification is very powerful feature to protect our google services (Gmail, Picasa etc) from hackers. More that 90% of users use SMS to get OTP (One Time Password) but this will be very problematic when someone travel internationally where you cannot use your home country sim because of high roaming charges.
In this case to avoid these login problems there are several alternatives which i am going to explain you now in detail.
1. PreLogin Google Services before travel.
If you login your google account in particular devices by checking the option “Do not ask for OTP on this device” google will never ask for OTP until and unless you clear the browser cookies. Google sets a browser cookie states that particular browser is already verified by OTP. Please do remember that this is purely a browser dependent, If you login with different browser or a device it will prompt for OTP.
2. Migrate to Google Authenticator App.
If you are a Android or iOS user, to avoid SMS service usage there is a smart option with small configuration. There is a option to bypass SMS service and Google Authenticator generates OTP at an interval of 20 seconds and is valid only for that duration.
But there is a drawback with this app, if your smart phone is lost you might be in trouble. There is another option which can be used as backup which is described below.
3. Generate Verification codes Backup.
The Verification codes backup is a txt file which contains a set of 10 codes. You should use this codes carefully because each code will be used only once. If you used all the 10 codes, you can again generate unique 10 set of codes.
You should make a note of these codes separately, but not in your email account. The set of codes looks something like i shown below.. (Those are just examples don’t try them, they will never work.)
4. Configuring a secondary mobile number.
The last but not the least option is you can add secondary mobile device to your google account. This can be of another country which you are travelling to.