All accounts in the beta group are now enabled to try the Mobile Authenticator.
We've made fixes to all aspects, there is an Android app update, please update the app. An iOS update is coming very soon.

Once again, after you add the authenticator to your account you'll be asked for the current code every time you log in to Steam. You can still choose to "remember" your login, so you won't have to type in a code every time you open the Steam client or store pages.

Please post issues and comments to the pinned thread for this. Thank you!

We've updated the sign up process and server side behaviors and enabled another ~2000 accounts. There is no app update at this time.

You may now add a phone number to your account without adding 2 factor, to access this functionality go to your "account" page ( find the drop down with your account name in the top left, and click on "account details".
Adding a phone number will give you another password recovery option in the near future. It also streamlines the process of signing up for 2 factor.

To check if your account has been enabled for the authenticator, go to the app's Steam Guard menu and select 'Change Settings'. If your account has the authenticator enabled you will see three choices, including one saying 'Get Steam Guard codes by phone'. (If you only see two choices -- one for 'Email' and one for 'None' -- then your account isn't enabled for the authenticator yet. Patience, please).

Once again, after you add the authenticator to your account you'll be asked for the current code every time you log in to Steam. You can still choose to "remember" your login, so you won't have to type in a code every time you open the Steam client or store pages.

Please post issues and comments to the pinned thread for this. Thank you!

We've updated the sign up process and server side behaviors and enabled another ~1000 accounts. There is no app update at this time.

To check if your account has been enabled for the authenticator, go to the app's Steam Guard menu and select 'Change Settings'. If your account has the authenticator enabled you will see three choices, including one saying 'Get Steam Guard codes by phone'. (If you only see two choices -- one for 'Email' and one for 'None' -- then your account isn't enabled for the authenticator yet. Patience, please).

Once again, after you add the authenticator to your account you'll be asked for the current code every time you log in to Steam. You can still choose to "remember" your login, so you won't have to type in a code every time you open the Steam client or store pages.

Please post issues and comments to the pinned thread for this. Thank you!

We're publishing updates to the iOS app and the Android app, and we've enabled authenticators on an additional 400 accounts.

The Android app has had a number of fixes to its launch and resume behavior, and we also fixed a few crashes and timeouts. The iOS app has a few minor bug fixes from its release last year, plus the authenticator feature.

To check if your account has been enabled for the authenticator, go to the app's Steam Guard menu and select 'Change Settings'. If your account has the authenticator enabled you will see three choices, including one saying 'Get Steam Guard codes by phone'. (If you only see two choices -- one for 'Email' and one for 'None' -- then your account isn't enabled for the authenticator yet. Patience, please).

Once again, after you add the authenticator to your account you'll be asked for the current code every time you log in to Steam. You can still choose to "remember" your login, so you won't have to type in a code every time you open the Steam client or store pages.

Please post issues and comments to the pinned thread for this. Thank you!

The first hundred participants have had their accounts enabled for the authenticator.

To see the user interface for this, go to the Steam Guard menu in the mobile app, select 'Change Settings', and if you're one of the people chosen you will see a choice for 'Get Steam Guard codes by phone'.

After you add the authenticator to your account, you'll be asked for the current code every time you log in to Steam. You can still choose to "remember" your login, so you won't have to type in a code every time you open the Steam client or store pages.