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Child Policy Guide: Who Counts as a Guest in a Japanese Hotel Room?

For a family of five or six, the child policy often decides which room you can book. The same 8-year-old can be “free” at one hotel and a full adult guest at the next. This guide sets out the rules hotels publish, with links to each official page.

Policies last checked: 2026-10-05. Rules vary by property and booking channel; the hotel’s own page wins.

Bed-sharing (“soine”): the rule behind most surprises

Japanese hotels commonly let a young child sleep in an adult’s existing bed without being charged as a guest. In Japanese this is soine (添い寝, “sleeping alongside”). Three conditions usually decide whether it applies:

  • Age cut-off. Among the hotels we checked it ranges from “preschool” (not yet in elementary school) through “elementary school and younger” and “under 12” to “18 and under”.
  • One child per adult or per bed. Most hotels we checked limit bed-sharing to one child per adult or one per bed.
  • No separate bed. As soon as the child uses a bed of their own, they are usually charged as a regular guest.
For a family of five with three children, this matters a lot. If one child is young enough to share, a room for four may be enough. If all three are school-age, you need five sleeping places, and the room’s maximum must be 5.

What hotels say: bed-sharing rules side by side

Hotel / brandFree bed-sharing ageLimitBaby cotExtra bed
Toyoko Inn
Budget business-hotel chain		Elementary-school age and youngerOne child per bedNot confirmedNot available
Vessel Hotels
Mid-range hotel chain		18 and under, staying with parents or grandparentsNo fixed number; depends on bed count and widthNot confirmedNot confirmed
MIMARU (apartment hotels)
Apartment-hotel brand		6 and under at check-in (up to 2 children per room)Up to 2 children aged 6 or under per room on top of the adult capacityFree baby crib and bed guard for infants under 2, limited stock, request in advanceNot confirmed
Tokyu Stay
Hotel chain with in-room washer-dryers		Not yet in elementary schoolOne child per adultAsk the hotel directlyNot confirmed
Keio Plaza Hotel Tokyo
Large full-service hotel		Preschool ageOne child per adultBaby cots for infants up to about 10 months who cannot yet stand; not available in some room typesNot confirmed
Hotel Century Southern Tower (Shinjuku)
Full-service hotel		Under 12, sharing an existing bedTwin/king rooms take 2 adults plus one bed-sharing childFree on request for babies under about 11 months, limited stockOnly in Scenic Twin rooms, for a fee, limited stock and not guaranteed
  • Toyoko Inn: A child who needs their own bed is charged the normal room rate. Extra towels and amenities may not be provided for bed-sharing children.
  • Vessel Hotels: Free bed-sharing only applies when children do not take a separate bed: one adult and one child in a twin room is charged as two guests. Breakfast is free for ages 0-5 and charged from age 6 (with a property exception).
  • MIMARU (apartment hotels): Children aged 7 and over count as adults toward room capacity.
  • Tokyu Stay: Elementary-school age and older are counted as adults.
  • Keio Plaza Hotel Tokyo: Bed-sharing is free only when the child does not need their own bed.
  • Hotel Century Southern Tower (Shinjuku): Connecting rooms exist only in one room category, are very limited and cannot be guaranteed.

The spread is wide: from “preschool only, one per adult” to “18 and under, as long as the beds are big enough”. Never assume one hotel’s rule applies to another, even in the same city.

Child rules for the room types we compare

RoomChild policy (from the official page)Baby cot
MIMARU SUITES Tokyo Nihombashi
Two-Bedroom Family Suite		Up to 2 children aged 6 or under (at check-in) are not counted toward adult capacity and may share a bed with an adult; age 7+ counts as an adult.Yes, free baby crib and bed guard rental for infants under 2; limited stock, request in advance
MIMARU Tokyo Akasaka
Connecting Japanese Apartment		Up to 2 children aged 6 or under (at check-in) are not counted toward adult capacity and may share a bed with an adult; age 7+ counts as an adult.Yes, free baby crib and bed guard rental for infants under 2; limited stock, request in advance
Keio Plaza Hotel Tokyo
Luxury Family Room		Preschool-age children (one per adult) can share an adult's bed free of charge if they do not need their own bed.Yes, baby cots for infants up to about 10 months who are not yet standing; may not be available in some room types
Tokyu Stay Shinjuku Eastside
Adjoining Room B		Children not yet in elementary school may share a bed free, one child per adult (one per bed); elementary-school age and older count as adults.Not confirmed
Citadines Shinjuku Tokyo
Stay Connected 3 Beds		Not confirmedNot confirmed
MIMARU Osaka Namba Station
Two-Bedroom Family Suite		Up to 2 children aged 6 or under (at check-in) are not counted toward the adult capacity and may share a bed with an adult; the room page lists capacity as adults + children (children = 6 and under).Free baby cribs and bed guards for infants under 2, limited stock; request in reservation comments / contact property in advance.
Hotel Keihan Universal Tower
Bunk Bed Superior Room		Not confirmedNot confirmed
MIMARU Kyoto Station
Two-Bedroom Family Suite		Up to 2 children aged 6 or under (at check-in) are not counted toward the adult capacity and may share a bed with an adult; the room page lists capacity as adults + children (children = 6 and under).Free baby cribs and bed guards for infants under 2, limited stock; request in reservation comments / contact property in advance.
Loisir Hotel Kyoto Toji
Family Room A (Toji View)		Bed-sharing is free for children 12 and under (infants and elementary pupils) only on official-site or phone bookings, max 1 child per adult/bed; via OTAs/agencies, elementary-age children cannot bed-share and pay adult rate. Children needing their own bedding pay the adult rate.Not confirmed
Booking channel can change the rule. Loisir Hotel Kyoto Toji, for example, states that free bed-sharing for children 12 and under applies only to bookings made on its own website or by phone; through travel sites, elementary-school children are charged as adults.

Baby cots and extra beds

Cots are usually free but limited, and often only for babies who cannot stand yet. Keio Plaza Hotel Tokyo states roughly up to 10 months; Hotel Century Southern Tower says under about 11 months; MIMARU lends cribs for infants under 2. Reserve the cot when you book, not at check-in.

Extra beds are less common in Japan than in many other countries. Toyoko Inn states it has none. Where they exist they are often limited to one room category, charged, and not guaranteed. Many hotel pages simply do not mention them, which is why many cells above say “Not confirmed”.

Ryokan and Japanese booking sites: child categories

Japanese booking sites often split children into more categories than “adult/child”. Rakuten Travel’s help centre treats elementary-school pupils as children (upper and lower grades) and preschoolers as infants, with four infant options:

  • meals and bedding,
  • meals only,
  • bedding only,
  • neither meals nor bedding.

The price depends on which you pick, so a toddler with “meals and bedding” costs more than one sharing a futon and eating from your plate. Rakuten also notes that you cannot add a child to an existing booking; you have to cancel and rebook.

Entering children on international booking sites

Booking.com asks for the age of every child in the search. Its documentation also explains that child rates apply only to children in existing beds (not cots or extra beds). Each property sets its own child policy and cot or extra-bed fees. In practice:

  1. Enter the real ages, not “2 adults + 3 children” with default ages.
  2. Open the property’s policy section before paying and check the age bands it lists.
  3. If the hotel’s own site states a different rule, the hotel’s rule is what you will meet at check-in. Ask the hotel if it is unclear.

Connecting rooms are a separate question

If no single room fits, two rooms are the fallback. Many hotels accept connecting-room requests but cannot guarantee them. Hotel Century Southern Tower, for example, says its connecting rooms are very limited, exist in one category only, and cannot be guaranteed. A few hotels sell the pair as its own room type, which is guaranteed at booking. Use the “sold as a pair” filter to find those.

Quick checklist for families of 5–6

  1. Write down each child’s age on the travel dates, not today.
  2. Count sleeping places needed: everyone over the hotel’s bed-sharing age needs one.
  3. Check the bed-sharing limit (per adult or per bed) for your exact hotel.
  4. Check whether the rule depends on booking channel.
  5. Reserve cots in advance; don’t count on extra beds unless the hotel’s page offers them.
  6. If you need two rooms, prefer a room type sold as a pair.

See Tokyo rooms for a family of 5

Sources