In brief: mobile data must be switched on for picture messages, for location updates when the phone is away from WiFi, and for the phone to register during pairing if it isn’t on WiFi. If something isn’t working and the phone is out of the house, this is the first thing to check.
How to switch it on
On the Sayph phone:
- Open Settings.
- Tap Connections.
- Tap Data usage.
- Switch Mobile data on.
What actually needs mobile data
- Picture messages (MMS). MMS does not work over WiFi alone – the phone must have mobile data on to send or receive photos, even at home.
- Location, away from WiFi. When the phone isn’t on a WiFi network it needs mobile data to report its position to Sayph Space. If the location shown looks hours out of date, mobile data being off is almost always the reason.
- Pairing. During setup the phone needs a connection – WiFi or mobile data – to register with your account.
Calls and ordinary text messages work without mobile data, which is why a phone can seem fine while photos and location quietly don’t.
Will it cost much?
No. The Sayph phone has no social media, video streaming or open internet, so it sips data rather than gulping it. Around 5GB a month should be sufficient for most children, and many low-cost SIM plans include more than that. See choosing a SIM for plans and what to look for.
Email help@sayph.one and tell us the handset (4G or 5G), the SIM network, and whether mobile data shows as on. We’ll get you sorted.
Last updated: 9 September 2026.
New to Sayph? Work through your first ten minutes – the whole setup on one page. More answers on the Support Centre.
