In short and in plain language
On average, children get their first own phone at age nine. The parents sign the contract. So the parents pay the costs.
Other firms can take money through the phone bill. This can happen with one tap on an ad. A block at the phone company stops this. The block is free.
A prepaid card has a fixed amount of credit. When it is used up, nothing more is charged. Do not turn on automatic top-ups.
Mobile internet can cost a lot in countries outside the EU. Turn off mobile data before the trip if you are not sure.
Write down rules with your child. For example: Do not buy anything without asking. Do not tap links in text messages.
Many families face a decision in these weeks: will the child get a first phone of their own for Christmas? On average, children are 9 years old when they get their first own smartphone (Bitkom). There is a lot of talk about screen time, age ratings and parental controls, and much less about the contract side. Yet that is where it is decided whether an ad tapped by mistake triggers a subscription on the phone bill, whether a school trip abroad gets expensive and whether the data allowance lasts until the end of the month. This article covers exactly that side: prepaid or contract, the third-party billing block, cost limits for data and roaming, how to handle an unexplained charge and a phone agreement that also covers money. We only touch on the settings on the device itself and refer to our detailed guide for those.
Key takeaways
- Children get their first own smartphone at 9 years on average (Bitkom). At that age the parents sign the contract, because children aged seven and over have only limited legal capacity (Section 106 BGB).
- The third-party block stops subscriptions and purchases from being billed via the phone bill. The mobile provider must set it up free of charge on request (Section 61 (2) TKG), for contracts and prepaid alike.
- A contract may run for an initial term of no more than 24 months, and the provider must also offer a contract of no more than twelve months (Section 56 (1) TKG). Prepaid caps costs at the credit loaded.
- For data roaming, the provider must offer a cost cap whose default limit is no more than 50 euros excluding VAT per month (Regulation (EU) 2022/612). Check mobile data before trips outside the EU.
- Dispute an unexplained third-party charge right away with the mobile provider and the third party; under the mobile guarantee, report the incident within 3 months of the transaction (Bundesnetzagentur).
- Costs belong in the phone agreement: 74 percent of parents whose child may use a smartphone argue with their child about the type or extent of use (Bitkom). Three firm rules on purchases, links and data bring clarity.
The first own smartphone at age 9
For its study report "Eltern in der digitalen Welt" (Parents in the digital world), the digital association Bitkom had 1,004 parents of children aged 6 to 18 interviewed by phone (Bitkom). The finding on getting started: from about 7 years of age children begin to use a smartphone, and they get a device of their own at 9 years on average (Bitkom). That is the age at which many children walk to school, sports or friends on their own and parents want to be able to reach them.
That is what matters to most families. Of the parents surveyed whose child owns a smartphone, 99 percent say it is important that their child has the device with them so they can be reached (Bitkom). For devices and media combined, parents spend 503 euros per child per year on average, of which 362 euros go to devices such as smartphones, tablets or laptops and 141 euros to digital media such as phone contracts, learning software or games (Bitkom). The share for contracts and content is smaller than the device price, but it is the easiest to steer: through the choice of plan, through blocks at the provider and through clear agreements.
What this article deliberately leaves out
Contract or prepaid: who signs, who pays
A nine-year-old cannot validly sign a phone contract alone. Anyone who has reached the age of seven has only limited legal capacity (Section 106 BGB), and a person comes of age on completing their 18th year (Section 2 BGB). For a declaration of intent that does not merely bring a legal advantage, a minor needs the consent of their legal representative (Section 107 BGB). In practice, therefore, the parents sign the contract or buy the prepaid card, and the child uses the SIM card. As a result, settings at the provider, blocks and disputes all go through the account holder, which means you.
For fixed-term contracts, the German Telecommunications Act sets clear limits. The initial term may not exceed 24 months, and before the contract is concluded the provider must also offer a contract with an initial term of no more than twelve months (Section 56 (1) TKG). If the contract then renews automatically, you can cancel it at any time with one month of notice (Section 56 (3) TKG). For a child's phone there is a lot to be said for a short commitment: how much data a child needs changes with age, and switching plans is easier with a short term.
Prepaid works differently: the child calls and goes online with credit that was loaded in advance. The law gives consumers the right to use mobile services on a prepayment basis (Section 64 (1) TKG), and when the contract ends the previous provider refunds the remaining credit on request (Section 64 (4) TKG). The biggest advantage for families: once the credit is used up, paid use stops instead of a bill growing. That only holds as long as no automatic top-up by direct debit or credit card is set up. Prepaid does not protect against third parties on its own, because their services can also be paid from prepaid credit (Bundesnetzagentur).
| Question | Prepaid card | Fixed-term contract |
|---|---|---|
| Commitment | depends on the plan; remaining credit refunded on request when the contract ends (Section 64 (4) TKG) | initially no more than 24 months, an offer of no more than 12 months is mandatory (Section 56 (1) TKG) |
| Cost cap | the credit loaded, as long as no automatic top-up runs | only if the plan or an add-on provides a spending cap |
| Third parties | can be deducted from the credit, block possible | appear on the bill, block possible |
| Data allowance used up | throttling or buying more from the credit, depending on the plan | throttling or a paid automatic data top-up, depending on the plan |
| Suits | getting started with a fixed monthly budget | children who need more data at a fixed price |
Some providers link an additional card to the parents' contract. That is convenient but has a catch: a third-party block may only apply to the number for which it was requested. When you apply, name your child's number explicitly and ask for confirmation of which numbers the block covers.
The third-party block: what it stops and what it does not
Third parties are companies that are not your mobile provider but bill their services via the mobile phone bill. The Bundesnetzagentur (Federal Network Agency) lists paid offers in app stores, public transport tickets, parking tickets, e-books, music and streaming offers, small donations and subscriptions as examples (Bundesnetzagentur). Such purchases are assigned via the phone number: each SIM card has a unique number that is used for purchases made on the mobile device (Bundesnetzagentur).
This is exactly the billing you can have switched off. End users can require their mobile provider to block, free of charge and at network level, the identification of their line for using and billing a service provided in addition to the connection (Section 61 (2) TKG). "At network level" means the block sits with the provider, not on the device. It therefore still works when the SIM card moves to another phone, and a child cannot turn it off in the settings. Setting it up is free, while lifting it later may cost a fee (Bundesnetzagentur).
Why this matters with children is described by the Verbraucherzentrale (consumer advice center): in many cases a careless or accidental tap on an ad banner is enough to land in a subscription trap; there are also known cases in which users were redirected to unknown pages without tapping anything and ended up with unwanted subscriptions of up to 9.99 euros per week (Verbraucherzentrale). With ad-funded apps, depending on the settings, a single thoughtless click can lead to a purchase (Verbraucherzentrale). Technically, the phone number is recognized in the background, which only works when the device is connected to the internet via the mobile network; this also applies to prepaid plans (Verbraucherzentrale).
Stricter rules have applied since February 1, 2020, the date by which the Bundesnetzagentur's ruling had to be implemented at the latest (Bundesnetzagentur). Since then, mobile providers may only bill third-party services if the customer was first redirected to a confirmation page of the mobile provider (redirect) or if the provider implements a set of protective measures that includes a money-back guarantee (Bundesnetzagentur). For subscriptions the redirect is mandatory in the second model as well, except after a sign-in via a so-called trusted partner login, while single purchases there run without a redirect (Bundesnetzagentur). In its 2025 annual report, the Bundesnetzagentur describes complaint numbers on this topic as still comparatively low (Bundesnetzagentur). The block still makes sense: a confirmation page only protects if someone reads and understands it, and with a nine-year-old that cannot be taken for granted.
It is just as important to know what the third-party block does not cover:
- Purchases by credit card, direct debit or invoice: the block only stops the ordering and payment route via the phone bill, other payment methods keep working (Verbraucherzentrale).
- Mobile payments in stores with a bank or credit card stored in an app: the third-party block does not stop this payment route (Verbraucherzentrale).
- Calls to expensive premium-rate numbers and short-code services: there is a separate block for certain number ranges, also free of charge (Section 61 (1) TKG).
- Data roaming outside the EU: here, roaming settings and the provider's cost cap help, not the third-party block.
- In-app purchases paid with a payment method stored in the app store account rather than via the phone bill: here, purchase approval by the parents in the device's family settings applies.
Full block or partial block
How to request the block
There is no setting on the phone for this: to set up a third-party block, the customer contacts their mobile operator (Bundesnetzagentur). The simplest order is this:
- Ideally, request it when signing the contract or buying the prepaid card; later, it works via the customer hotline or the online customer area (Verbraucherzentrale).
- If the hotline or portal does not help, apply in writing: the Verbraucherzentrale provides a template letter for this, which goes to the mobile provider (Verbraucherzentrale).
- Name your child's phone number explicitly, especially with several cards on one contract, and ask for written confirmation of the block.
- In the same letter, request the block for expensive number ranges and short-code services, which is also free of charge (Section 61 (1) TKG).
- Check the first bill or the credit overview: if third-party items appear there, the block is not active yet or not for this number.
- After a plan change, a new SIM card or a number port, ask whether the block is still in place.
Cost limits and data: where else the money goes
The second cost driver is the data allowance. Anyone who looks something up now and then and answers chat messages on the go should do fine with a data package of 2 to 6 gigabytes per month, according to the Verbraucherzentrale (Verbraucherzentrale). Anyone who often streams videos or music over mobile data needs a larger package (Verbraucherzentrale). At home, the child's phone therefore belongs on the Wi-Fi, and updates should only download over Wi-Fi, as the Verbraucherzentrale advises (Verbraucherzentrale). If the signal does not reach the kids' room, Wi-Fi optimization throughout the house helps.
It gets expensive when the plan automatically adds more data after use. Once the allowance is used up, the connection is usually throttled; cost traps lurk when the plan includes an automatic data top-up or when further packages can be added for a fee (Verbraucherzentrale). For a child's phone, throttling is the friendlier limit: the child notices that the data is used up, and the bill stays the same. When signing up, ask specifically whether an automatic data top-up is built in and how to switch it off.
Even a calling flat rate does not include all numbers. The Verbraucherzentrale advises avoiding calls to paid numbers, for example with the prefixes 0900, 0180, 0137, 0700 or 032 (Verbraucherzentrale). Rather than having the child memorize prefixes, the network-level block for certain number ranges and short-code services is the simpler route; it is free of charge, and only unblocking later may cost something (Section 61 (1) TKG).
Within the EU, flat rates and data allowances can be used just as at home; it is different in non-EU countries, on ships and on planes (Verbraucherzentrale). That affects families on school trips, on a ski vacation in Switzerland or on a ferry. For data roaming, the provider must offer a cost cap: a default limit is close to 50 euros excluding VAT per monthly billing period, but not above it, and it applies to all customers who have not chosen another limit (Regulation (EU) 2022/612). At 80 percent of the limit, a notification is sent to the phone (Regulation (EU) 2022/612). Outside the EU, this function only works if the visited network allows real-time monitoring; otherwise the customer receives a text message saying so on arrival (Regulation (EU) 2022/612). The regulation applies until June 30, 2032 (Regulation (EU) 2022/612). If in doubt, switch off mobile data before the trip as a precaution, as the Verbraucherzentrale recommends (Verbraucherzentrale).
Third-party block
Requested from the provider, confirmed in writing and set up explicitly for the child's number.
Premium-rate numbers
Block for expensive number ranges and short-code services requested in the same letter.
Automatic data top-up
Switched off or never booked, so that throttling kicks in after the allowance instead of a top-up.
Roaming
Cost cap active, data roaming clarified before trips outside the EU, mobile data off when in doubt.
Store account
No payment method stored in the child's account, purchases only after approval by the parents.
First bills
Look at the first bills or credit deductions together and clear up unknown items right away.
Kid account and family approval: the essentials on the device
On the device itself, there are two cost questions. First, the child needs their own account in the operating system's family group, not a parent's account, otherwise they shop with the parents' payment details. Second, purchases and new apps should only be possible after the parents approve; the common smartphone systems offer approval within the family for this. The Verbraucherzentrale also recommends setting the app store so that purchases require a password prompt or identification (Verbraucherzentrale).
Many parents of younger children already use such features: of the parents of 6- to 9-year-olds who are allowed to use a smartphone, 90 percent have activated parental control features or age-appropriate settings (Bitkom). How to set up usage times, age ratings and app approvals in detail, and how router schedules add another layer, is covered in our guide on screen time for children. There you can also read why location sharing with a sense of proportion works better than secret monitoring.
If the child gets a used phone from the family, it should be fully reset first so that no accounts, payment details or photos of the previous owners remain on it; the article Selling an old phone: erasing data safely shows how to do this properly. With very old models, it is also worth checking the network indicator and VoLTE; what to look for is explained in the article on the 2G shutdown and old phones. If contacts and photos are to move from the old device to the new one, our data transfer service takes care of it.
An unknown charge on the bill: what to do
If an unknown item appears on the bill despite all precautions, start by looking at the details. If a bill includes claims by third parties, it must state their name and address for service as well as a local landline number or a free customer service number (Section 62 (2) TKG). In many cases, what appears there is not the actual subscription operator but a billing company that bills on its behalf (Verbraucherzentrale). Ask within the family as well: if others share the smartphone, the Bundesnetzagentur advises checking whether anyone can match the amount or the provider name (Bundesnetzagentur).
- End the subscription: cancel the unwanted subscription with the billing company or directly with the operator; this is also a prerequisite for getting the money back under the mobile guarantee (Verbraucherzentrale).
- Dispute: object to the item promptly and with reasons at the mobile provider and also at the third party (Bundesnetzagentur). For objections to a bill, the law sets a period of eight weeks after receipt (Section 67 (2) TKG).
- Use the guarantee: if your provider has signed the mobile guarantee, report the incident within 3 months of the transaction (Bundesnetzagentur). Up to a limit of 50 euros, the guarantee applies without further proof; excluded are, among others, purchases properly confirmed via the redirect or triggered after a trusted partner login (Bundesnetzagentur).
- Control the payment: with direct debit, check whether to revoke the debit and reissue it minus the disputed item (Bundesnetzagentur). With a partial payment, state explicitly what it is to be applied to, otherwise it is split proportionally across all claims on the bill (Section 62 (3) TKG).
- Report: report dubious third parties using the Bundesnetzagentur complaint form and attach a copy of the bill and the phone number (Bundesnetzagentur).
A common worry is that the provider will block the child's phone over a disputed item. The law sets narrow limits here: a block for late payment is only allowed if the consumer, after repeated non-payment, is in arrears with at least 100 euros (Section 61 (4) TKG), and it must be announced in writing at least two weeks in advance (Section 61 (4) TKG). Disputed third-party claims without an enforceable title are not counted (Section 61 (4) TKG). You should still pay undisputed items as usual so as not to risk a block of the line (Verbraucherzentrale).
"Our phone rules": an agreement that includes costs
Technical blocks catch a lot, but they do not replace talking. Arguments happen anyway: 74 percent of parents whose child may use a smartphone argue with their child about the type or extent of use (Bitkom). And 47 percent of parents with a set time limit report that their child often uses the smartphone longer than agreed (Bitkom). Bitkom recommends that parents set rules on usage times and standards of behavior together (Bitkom). A written agreement that both sign makes such rules visible, and it is the right place for the cost questions that otherwise get lost in everyday life. A template to start with:
- No purchase and no subscription without asking first, not even for a game extra, a wallpaper or a free trial.
- Do not tap links in text messages and chats, ask first.
- Keep an eye on the data allowance together; once it is used up, we wait until the end of the month instead of buying more.
- Install new apps and messengers only after talking it over.
- We share our location for specific situations that we have discussed beforehand.
- If the phone gets lost, the child says so right away so that the SIM card can be blocked.
The rule on links has a solid reason. In 2025, the Bundesnetzagentur received a total of 28,036 complaints about unlawful messages sent via text message or messenger services (Bundesnetzagentur). With a number of their own, a child can receive such messages too. How to recognize scam messages and what to do in an emergency is explained in our article Spotting phishing and fake calls.
With messengers and social networks, it pays to look at age. If an online service processes a child's data based on consent, this is only lawful without parental approval once the child has turned 16 (Art. 8 GDPR). Many services also set their own minimum age in their terms of use. For starting on social networks, parents would like an age of 14 years on average (Bitkom). What applies to your child belongs in the agreement, as does the question of who the child shares their location with.
The handover: contract first, then the device, then the wrapping paper
So that nothing is missing on Christmas Eve, it helps to follow an order that starts with the contract and ends with the wrapping paper. Confirmation of a block can take a while, which is why the steps at the provider come first:
- Choose a plan and order the SIM card; request the third-party block and the premium-rate block at the same time.
- Wait for the written confirmation and check the automatic data top-up and the roaming cost cap.
- Update the device, create a separate kid account in the family group and turn on purchase approval.
- Save the parents' emergency contacts and make a test call with the new SIM card.
- Prepare the phone agreement so that it is on the table when the gift is unwrapped.
How to prepare a gift device in general, with updates, an access letter and a separate handover appointment, is covered in the guide Gifting technology: set up devices before Christmas. For a child's phone, the access also stays with the parents: login details and recovery codes for the kid account belong in the parents' records, not on a note in the kids' room.
How Technik daheim helps with a child's first phone
We come to your home in the Hildesheim area and the Leine valley and set up the first phone so that it is ready under the tree: kid account in the family group, purchase approval, updates, emergency contacts and the connection to your Wi-Fi. Together we go through your contract, show you where to request the third-party block, the premium-rate block and the cost cap from the provider, and check after confirmation that everything is in place. You submit the request yourself as the account holder; we help with the wording and the customer portal. You can find more about our offer under tech help for families.
What a home visit costs is listed clearly on our pricing page. All other areas we cover, from the router to the TV, are listed under services. Use our contact form to tell us which device and which plan you have in mind, and we will bring what we need to the appointment.
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