Players must register a unique phone number to their accounts in order to queue for Ranked matches. If a phone number is removed from an account after registration, a new number can be added, but there will be a three-month waiting period before that same number can be registered again.
Once a Dota account has become eligible for ranked, an "Associate Phone With Dota" option will display within the find match window. After clicking on "Associate Phone With Dota", the phone number registered to your Steam account will automatically be registered to your Dota account.
If a phone number has not yet been added to the Steam account you are using, you will be required to do so prior to adding it to your Dota account.
If you are able to successfully register a number to your Steam account, it will work for Dota as well. Online services that provide virtual phone numbers do not qualify. this includes popular VOIP providers.
Please note that we do not make exceptions to this requirement. Should your number not qualify, you will need to use a different phone number.
See the official Steam Mobile site for information on how to register a qualifying number to a Steam account.
From the find match window under ranked, select 'Remove Phone'.
Note: the three month cooldown will still apply to this phone number before it can be added to another Dota account.
You may remove the old phone number from your Dota account and add a new number at any time.
Note: the three month cooldown will only apply to the number that was removed.
If a qualifying phone number cannot be added to your Steam account, you will be unable to add a phone number to your Dota account. Ranked Matchmaking will not be available unless a phone number is added to the account.
No, the Steam Guard Mobile Authenticator is not required to register a phone number to your Dota account.
We still recommend that you use the Steam Guard Mobile Authenticator. In addition to providing an extra layer of security for your account, adding the Steam Guard Mobile Authenticator gives you full access to trading and the Steam Community Market.
More information can be found here: Steam Guard Mobile Authenticator
If you are having an issue with the Steam overlay, make sure to follow all of the steps outlined in the Steam Overlay FAQ.
If you are not able to get the overlay working, you can still link a phone number by temporarily disabling the Steam overlay for Dota 2. You can do this by right-clicking the game in your Library > selecting 'Properties' > and then un-checking the 'Enable Steam Overlay In Game' box