Family Guide
Family and Kids' SIMs in Japan: A Guide for Foreign Families
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If you only read this part
The online-only plans (LINEMO, povo, ahamo) have no family discounts, but their base prices are low enough that a whole family usually still pays less than the big three's discounted family bundles. A child's line is contracted by the parent, with the child registered as the user. Filtering must be offered by law for anyone under 18.
Section 01
Do Family Discounts Actually Save Money?
The big three's family discounts run along the lines of 1,100 yen off per line when you have three or more. The discount looks large until you remember the base prices it discounts. Undiscounted LINEMO or ahamo beating a discounted flagship plan is not an edge case; it is the normal outcome.
Simple math for a family of four: flagship unlimited plans with family discounts applied land around 20,000 yen a month and up. The same four on LINEMO: two parents on Best Plan V (2,970 yen each), two kids on Best Plan (990 yen each), total 7,920 yen. Free family calling and the other bundle perks do not come close to closing that gap.
Section 02
How Contracts for Kids Work
Minors cannot hold contracts in their own name, so the parent signs as the contract holder and registers the child as the designated user. The online-only plans all support this user registration. You will need the child's age documentation (residence card, passport) at signup.
When the child turns 18, a name transfer moves the contract into their own name.
Section 03
Filtering Is the Law
Under the Youth Internet Environment Act, carriers must provide filtering for lines used by anyone under 18. Beyond the carriers' own filter services, the OS-level tools (Google Family Link on Android, Screen Time on iPhone) handle practical management well.
Parents can opt out of filtering, but the opt-out is itself a formal step, and you will be asked about it at signup. Decide your policy before you apply and the process goes smoothly.
Section 04
Keeping It Manageable
- One card for every linePutting the whole family on the same card or bank account prevents the classic foreign-family failure: a missed payment silently suspending a line.
- One name on every contractWith user registration handled, one parent account manages plan changes, upgrades and cancellations for everyone.
- Kids' phones are a flagship-brand thingDedicated kids' handsets (kids keitai) are sold through docomo and the other main brands. On the online-only plans, the setup is a normal smartphone plus filtering.
The Verdict
The Family Setup
Parents (main lines)
LINEMO 30GB or ahamo
Rural: ahamo. City: LINEMO. Same logic as for anyone else on this site.
Kids
LINEMO 3GB at 990 yen
Parent-held contract with user registration. The stepped plan caps a heavy month at 10GB and 2,090 yen. Set up filtering before the phone changes hands.
For the latest plan and campaign details, see the official LINEMO site.
FAQ
Frequently asked questions
Can I get a kids' phone (kids keitai)?
Dedicated kids' handsets are sold through the main flagship brands (docomo and others). On the online-only plans, the equivalent is a normal smartphone with filtering configured.
Should every contract be in one name?
For day-to-day management, yes. But plan a name transfer when a child turns 18; without a contract in their own name, future MNP moves and phone purchases get awkward.
What trips up foreign families at screening?
Payment methods. Plans that accept bank transfer (LINEMO, ahamo) are the accessible options before a Japanese credit card exists.