"Two power banks per passenger" — that has been the rule on flights to and from Japan since April 24, 2026. The Ministry of Land, Infrastructure, Transport and Tourism (MLIT) published it on April 14, following an emergency amendment to the international standards that the ICAO Council approved on March 27, effective the same day. Working from the official announcements available as of July 29, 2026, this article sets out how many you can carry, up to how many watt-hours, where to keep them, and what you may not do in the cabin. It also covers the other half of the problem — charging in Japan, from the PSE mark to rental batteries and 100V sockets.

What changed: two steps, July 2025 and April 2026

Japan's cabin rules tightened in two steps over the past year. The first came on July 8, 2025. In an announcement dated July 1, MLIT added two requirements: power banks must not be stowed in the overhead bins, and any charging on board has to be done in a place where the battery's condition can be observed at all times. The ministry pointed to the January 2025 fire aboard an Air Busan aircraft at Gimhae Airport in South Korea, where, in its words, an igniting power bank has been flagged as a possible cause, and noted that smoke and fire incidents had also occurred on domestic flights.

The second step took effect on April 24, 2026. After the ICAO Council approved an emergency amendment to the international standards on March 27, effective immediately, MLIT amended the ministerial public notice (kokuji) that sets the standards for carrying dangerous goods by air. Three rules were added on top of the existing ones: carry-on power banks are limited to two per person (160Wh or less), you may not charge a power bank on board, and you may not use a power bank to charge another device on board.

ICAO's own statement makes the same points: the devices are limited to two per passenger, recharging during flight is prohibited, and crew may continue to carry and use power banks in line with operational requirements. The amendment was circulated to all 193 ICAO member states, so this is not a Japan-only rule — each country writes it into its own regulations.

Within Japan, the Scheduled Airlines Association of Japan announced on April 14, 2026 that its member airlines would apply the change uniformly from April 24. The carriers have posted their own notices too. ANA's, also dated April 14, 2026, says two power banks per passenger may be carried on board; Peach Aviation's announces the change "for boarding from April 24, 2026"; and JAL carries the same information on its own site. Foreign carriers implement the ICAO standard through their own national rules, so start dates and any stricter house rules can differ from airline to airline.

The core rules: never checked, 160Wh maximum, two per person

MLIT's passenger-facing summary — attachment 1 to the announcement — runs to seven points. Here they are as they stand from April 24, 2026.

The logic starts from "not in the hold." A battery that begins smoking in the cargo compartment is one nobody can see. Overhead bins were added to the ban for the same reason: behind a closed door, trouble is noticed late.

The flip side is that handing your battery over by accident puts you in breach. The trap to watch for is gate-checking — a bag you meant to carry on being taken at the boarding gate.

  • Never put a power bank in checked baggage — it is prohibited; it has to travel in the cabin with you
  • 160Wh maximum — anything rated above 160Wh cannot be carried at all
  • Protect each one against short circuits — tape the terminals, use a case or pouch, and do not put several batteries or metal objects in the same bag
  • Do not stow it in the overhead bin — keep it in the seat pocket or otherwise within reach
  • Two power banks maximum — added on April 24, 2026
  • Do not charge a power bank from the aircraft's power supply — added the same day
  • Do not charge other devices from a power bank (charge them from the aircraft's own outlets instead) — added the same day

How to count to two: power banks, spare cells and built-in batteries

To count correctly, it helps to know that the public notice distinguishes three things: (1) power banks — devices with a built-in lithium battery whose purpose is to supply power to other electronics; (2) spare batteries — camera spares, or cells removed from a device; and (3) batteries built into equipment such as phones and laptops.

The numeric cap applies to the first category. Appended Table 18 of that notice bars power banks from checked baggage and limits them to "two" in carry-on. The watt-hour figure makes no difference here: as long as each is 160Wh or less, the total is two.

Spare batteries have a separate allowance. They are also carry-on only, and the basic limit is likewise two — but Appended Table 18 states that spare lithium-ion cells rated 100Wh or less (and spare lithium-metal cells with 2g or less of lithium) "shall not be counted toward the quantity," and MLIT's attachment 1 says the same in plainer terms, printing "spare batteries of 100Wh or less: no quantity limit" against all three of the power-bank scenarios it illustrates. Spares of 100Wh or less are never counted, in any of the three cases. What does get counted is the spare rated above 100Wh and up to 160Wh: carry one alongside a power bank in the same class and, in the notice's wording, they are "counted together with that power bank, up to two." So two power banks above 100Wh leave no room for a spare in that class; one leaves room for one spare; none leaves room for two.

Phones and laptops do not count toward the two. Their built-in batteries must be 160Wh or less, and if the device travels in checked baggage it has to be switched off, among other conditions. Smart luggage with a built-in lithium battery must be carried in the cabin if the battery is rated above 2.7Wh, and if the cell is removed, the spare-battery rules apply to it. There is a separate provision for electric wheelchairs and mobility aids: one spare lithium-ion battery of 300Wh or less may be carried in the cabin, with two batteries of 160Wh or less each counting as one. If this applies to you, tell the airline in advance rather than at the counter on the day.

Reading the Wh figure — and where the mAh math goes wrong

The watt-hour rating is usually printed on the casing. If you can find a figure in Wh, that is the number that matters. If you cannot, work it out from the rated capacity and the rated voltage.

MLIT's attachment 1 takes a 27,000mAh, 3.7V product as its worked example and arrives at 99.9Wh. There is a trap here. In its FAQ on the Electrical Appliance and Material Safety Act, the Ministry of Economy, Trade and Industry (METI) states that a product with 3.7V cells that steps its output up to 5V must be labeled with 5V. So the rated voltage printed on the case may be the output figure, and using it will overstate the watt-hours. If there is a Wh figure on the body, trust that; if not, estimating on cell voltage of roughly 3.6 to 3.7V is closer to reality.

At 3.7V, the rough landmarks are 37Wh for 10,000mAh, 74Wh for 20,000mAh, about 100Wh for 27,000mAh and about 160Wh for 43,000mAh. Everyday 10,000 to 20,000mAh packs are nowhere near 100Wh, so for most travelers the binding constraint is the two-unit cap rather than the watt-hour ceiling.

Avoid products with no markings at all. If you cannot show that the battery is 160Wh or less, being turned away at security is a fair outcome.

  • Watt-hours (Wh) = rated capacity (Ah) × rated voltage (V)
  • Watt-hours (Wh) = rated capacity (mAh) × rated voltage (V) ÷ 1,000

A pre-departure check so you don't surrender it at the airport

"If they won't let me carry it, I'll just check it" does not work, because putting a power bank in checked baggage is itself prohibited. MLIT goes further, warning that a battery you could not carry on may also be refused as air cargo by courier services, and telling passengers to declare it and follow the carrier's instructions. Your options at the airport are narrow, so settle this the night before.

The insulation step is spelled out: ANA asks passengers to protect the terminals with tape, or to put each battery in its own plastic bag. It looks fussy, but individual insulation is one of the points that can carry a penalty.

Count anything you buy while you are here. Buy one power bank at an electronics store in Japan and it fills one of your two slots — the impulse purchase is the one you end up leaving behind.

  • Lay out every power bank you own and check the Wh marking, or the mAh and V figures
  • Leave anything above 160Wh at home — you cannot check it, and nothing can be done about it at the airport
  • If you have three or more, cut down to two; send the rest by ground transport or leave them behind
  • Tape the terminals, or give each battery its own pouch or original box; never in the same bag as keys or coins
  • Pack them where you can reach them — security may ask you to take them out
  • If your bag is gate-checked, take the batteries out before you hand it over

On board: what to do, and which rules carry penalties

What you actually do on board is simple. Keep the battery out of the overhead bin — the seat pocket or your own bag is fine — and do not charge anything with it. Charge your phone or laptop from the aircraft's own USB port or outlet instead. Peach Aviation's notice spells it out: you may not use a power bank to charge a phone in the cabin, and you may not charge a power bank from the seat's USB port.

MLIT's attachment 1 also marks which of the seven points can attract a penalty. Breaching items 1 (no checked baggage), 2 (160Wh or less), 3 (individual insulation), 5 (two maximum) and 6 (no charging a power bank on board) may be penalized under the Civil Aeronautics Act. Item 4 (overhead bins) and item 7 (not charging other devices) are worded as requests. ANA's notice draws the same distinction: charging a power bank is "prohibited," while charging a device from one is something passengers are asked to refrain from.

In practice you can ignore the distinction. If the aircraft has seat power you can charge from it, and if it does not, boarding with everything at full charge usually covers a few hours. Deciding simply not to use a power bank in the cabin removes the question entirely.

Crew are exempt where the job requires it, and this is stated on the Japanese side as well: the Scheduled Airlines Association of Japan's joint release — attachment 2 to the MLIT announcement — says an exemption is recognized for crew members where it is necessary for their duties. ICAO likewise says crew may continue to carry and use power banks in line with operational requirements. Seeing a flight attendant using one is not a signal that passengers may do the same.

Buying and renting in Japan: the PSE mark and shared power banks

If you are buying a power bank in Japan, look for the round PSE mark. Power banks were brought under the Electrical Appliance and Material Safety Act by a revision to the relevant public notice on February 1, 2018, and after a one-year transition, selling one without the PSE mark has been prohibited since February 1, 2019, existing stock included. The scope covers products whose individual cells have a volumetric energy density of 400Wh/L or more.

The labeling duty goes beyond the mark itself. METI requires the round PSE mark plus the notifying business's name, the rated voltage and the rated capacity. Put the other way round, a legitimately sold product carries the numbers you need to work out watt-hours. A second-hand or unbranded unit missing them leaves you with no way to prove it is allowed on board.

Renting is the other option. Shared power banks sit in convenience stores, stations and phone shops; ChargeSPOT, operated by INFORICH Inc., states on its official site that it had 59,784 stands nationwide as of December 2025. Its published rates start at 165 yen for under 30 minutes and run to 500 yen for under six hours, 570 yen for under twelve and 640 yen for twelve to under twenty-four, with 360 yen added for each further 24 hours (rates as listed on the official site, checked July 2026; consumer prices in Japan are displayed tax-inclusive).

Two things matter for visitors. A rented battery still counts toward your two, and it has to be returned before you fly home. ChargeSPOT states that a compensation charge of 4,080 yen applies if a battery is lost or damaged. Leave the country holding one and it still counts toward your two, you cannot check it, you cannot charge anything with it on board, and you have nowhere to return it.

Outlets in Japan, and the last thing to check before you fly

The charging environment is worth knowing too. According to the Japan National Tourism Organization (JNTO), the voltage is a uniform 100V nationwide, with 50Hz in eastern Japan and 60Hz in the west, including Nagoya, Kyoto and Osaka. Sockets take two flat parallel pins — the shape sold as a "Type A" travel adapter — and few of them have a third, grounding pin.

Most USB chargers and laptop adapters are fine as they are: if the casing reads "INPUT 100-240V," you need no transformer, only a plug adapter if your pins do not fit. JNTO notes that appliances not rated for 100V do need a step-down transformer, and that conversion plugs and transformers are easy to find in the electronics districts of Tokyo's Akihabara and Osaka's Nipponbashi, or at large retailers such as Yodobashi Camera and Bic Camera.

For power on the move, JNTO says newer shinkansen models have outlets next to the window seats and suggests asking for a window seat when you buy the ticket. Some hamburger chains and family restaurants have outlets as well, though not every branch does.

One last point. Everything above reflects announcements published by MLIT, ICAO and the airlines as of July 29, 2026. The pace — ICAO approving an emergency amendment on March 27 with same-day effect, Japan applying it on April 24 — shows how quickly this area moves. MLIT itself warns that individual airlines may set stricter rules and that passengers should follow their instructions. Open your airline's own power bank notice once before you fly; ANA, JAL and Peach Aviation each maintain a dedicated page for it.

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