Yes! It's possible to read offline while using the mobile app for smartphones and tablets. Just add a title to your library while you have internet access (via Wi-Fi or mobile data). Once the title is in your library, you can read it while you're offline as well.
Unfortunately it's not possible to read offline when using the website. However, we have a Send-to-Kindle feature as part of the subscription-based Blinkist Premium, which enables you to read Blinks offline on your Kindle.