If you didn't see an SMS option for setting up reminders in Google calendar, it may be that Google doesn't know your cell phone number. Before Google Calendar can send you a text message, you need to tell it where to send that message. To do that, click Settings in the upper-right corner of Google Calendar. In the Calendar Settings window, click Mobile Setup. Choose your country from the Country list. Then, type your mobile number in the Phone number field. Don't forget to include the area code and the country code. After that, choose your cell phone service provider from the Carrier list. Depending on where you are and which companies that Google deals with, your carrier might not be in the list.

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Finally, click the
Send Verification Code button. This sends a message with a six-digit code to your mobile phone. Once you receive that message, enter the code into the
Verification code field and click the Finish setup button. Google Calendar can now send text messages to your mobile phone. Now you can begin setting up SMS reminders in Google calendar.