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SIM card for a kids smartwatch: which one and how to set it up

Most setup problems with a kids smartwatch come from the SIM card. Here is what the SIM needs, how to prepare it and how to pair the watch with the app, step by step.

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What to look for

A nano-SIM with mobile data

The watch uses mobile data to send its location and talk to the app. Without data, the app shows nothing. A data-only SIM, like those for tablets or routers, is not enough if you want calls. The SIM is your own and is not included with the watch.

Minutes and caller ID

For voice calls, the plan needs call minutes. Caller ID (number display) must be on, because the watch recognises approved contacts by their number.

PIN off, number shown

Remove the SIM PIN on a phone before inserting it in the watch, otherwise the watch cannot unlock the card. If you hide your caller ID on your own phone, switch that off so the watch recognises you when you call.

Prepaid or contract, your choice

Both work. Prepaid gives you a fixed cost; a contract or a family add-on SIM avoids running out of credit. Keep an eye on data use in the first weeks.

4G, bands and VoLTE

Many 4G watches make calls over VoLTE (voice over 4G). Ask your operator whether the SIM and plan have VoLTE switched on. If you want to check the model's 4G bands with your operator too, ask us for them.

Cosmote, Vodafone or Nova?

All three offer prepaid and contract plans. What matters for the watch is a SIM with data, minutes, caller ID and VoLTE where needed. Beyond that, pick the operator with the best coverage where your child spends the day.

Setup tips

  1. Put the SIM in a phone first and switch off the PIN in the security or mobile network settings, under "SIM PIN" or "SIM card lock". Check that data works and that the number shows when it calls.
  2. Switch the watch off, insert the nano-SIM, then switch it on and wait until it shows mobile signal.
  3. Install the companion app (SeTracker or SeTracker2, as stated in the watch's manual), create an account and scan the QR / registration code of the watch.
  4. Add the parents and family as contacts and SOS numbers, then make a test call in both directions.
  5. Check data use after a few days and adjust the plan if needed.
  6. If you use prepaid, set a reminder to top up or turn on automatic top-up if your operator offers it. A watch without credit is a watch without location.

Good to know before you buy

  • The SIM and the mobile plan are not included. Their cost depends on your operator and the plan you choose.
  • Not every plan or operator setting works with every watch. Confirm with your operator that the plan includes data and 4G/VoLTE.
  • If the SIM runs out of credit or data, the watch stops reporting its location and may not make calls.
  • The companion app provider (SeTracker) processes the watch's location data. Read its privacy policy before you register.
  • For whether a specific model works with your operator (4G bands, VoLTE), ask us before you order.

Questions parents ask

What size SIM does the watch take?

A nano-SIM, the small size used by most current phones.

Can I use a prepaid SIM?

Yes, as long as it has mobile data, caller ID and no PIN. For calls it also needs minutes or credit. Like every prepaid SIM in Greece, it is registered to its holder's details, so a parent usually takes it out in their own name.

Cosmote, Vodafone or Nova: does it matter?

All three offer plans with data, prepaid and contract. We do not recommend a specific plan. Make sure the SIM has data, minutes, caller ID and VoLTE, and choose the operator with the best coverage at home, at school and in the village where your child spends the summer.

The app shows the watch offline. What should I check?

Usually the SIM: check that mobile data is active and has credit, that the PIN is removed and that the watch has signal. Then restart the watch. If it still doesn't connect, contact us.

Who sees the location data?

The family members you add in the app, and the app provider (SeTracker), which processes the data. Read its privacy policy, and only connect a watch worn by a child you are responsible for.

How do I check whether the SIM has VoLTE?

Ask your operator, in store or through customer service, whether that SIM and plan have voice over 4G (VoLTE) switched on. It is worth confirming, because without it a 4G watch may send its location normally but fail to make calls.

Can I use a data-only SIM?

The watch will send its location to the app, but it will not make or receive normal calls. If you want your child to call you, you need a plan with call minutes.

Does the watch work on holiday abroad?

If the SIM has roaming switched on, the watch can work in other EU countries, where "roam like at home" applies. Ask your operator before you travel, because coverage and bands differ between countries.

Other guides

Kids smartwatch with GPS: the complete guide SOS watch for elderly parents Which watch for which age First setup: pairing with the SeTracker app Kids smartwatch with video calls Safety and privacy on a kids smartwatch Smartwatch or phone for a child aged 6–10? Waterproof kids watch: what IP67 really means A smartwatch as a gift for a child

Not sure which watch to pick?

Tell us who the watch is for and what matters to you. Our team in Thessaloniki, the official Wonlex dealer in Greece, will help you choose and set it up.

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