lost phone with (UK) sim card, in Thailand, new phone won't let me sign into google account

Sign into your Google account at https://myaccount.google.com/ use a computer if necessary, and check the account options for the registered phone number here. https://myaccount.google.com/security

 

Hey, you can talk to the carrier company when you'll reach your country and get the same number again in order to access all your accounts and other stuff related to that number. It's the best way possible to retrieve your accounts.

I also faced this issue and Google won't let you in unless you're signing in from a familiar phone that you've used in the past to log in or Google had already recognized as the trusted device.