Yes! Carbon is designed for mobile, tablet and desktop and works equally well on all devices. It is designed to work on any screen 360px wide and above. A recent survey showed over 70% of users intend to use Carbon mostly on mobile.
If you are on Android you can get the Carbon app from Google Play Store here: https://play.google.com/store/apps/details?id=com.carbon.social
If you are on iOS, simply go to carbon.social and use the web app – it is identical to the Android mobile app.
You can easily login on mobile without the need for MetaMask, by first joining Carbon with MetaMask and then generating your login code, and using that code on other devices including your phone or tablet. The login code can be generated in the Account section.