Yes, we designed it especially that way.
Even when you’re totally offline, without a data or cellular connection, you can still find the 3 words for your location and navigate to other locations (using Compass mode). This is because our app uses a GPS signal to work, which has near-universal coverage wherever you are in the world. However, we find it works best when you’re outside and able to see the sky above you.
To share a what3words address over the phone or in a text message, you need phone signal or a data connection. You also need a data connection to load maps, or share an address in other apps or on social media.