Mercari Japan Return Fraud and Item Swaps: What Sellers Should Record Before Shipping

Last reviewed October 16, 2026 · 18 min read · By the PEA team (Lumina Spark)

日本語版 (Japanese version)

Short answer: The best protection against item swaps and other return fraud is a record, made before you ship, that identifies that exact item. Photograph the whole item plus close-ups of the model and serial number, marks unique to that item, and the accessories, then film packing it without stopping, from showing the serial number to sealing the box, and ship with tracking. When a buyer sends "damage" photos, compare the same spots with your own photos; using edited images that make an item look broken in messages or to support is prohibited by Mercari. When a return arrives, film it from before opening, compare it with your records, and if something is wrong, contact support before you complete the return. Mercari's Full Compensation Support Program has conditions. You don't need to suspect buyers from the start; this is about being ready just in case. This article is general information about Japan, not legal advice.

What return fraud and item swaps look like

On Japanese flea-market apps, "item swap fraud" (surikae sagi) describes a buyer claiming an item was fake or broken, getting a return approved, and sending back something other than what you shipped (a fake, a broken unit, or a similar-looking item). Abuse of the return process like this is also loosely called "return fraud" (henpin sagi); this is not an official Mercari term.

Japan's National Consumer Affairs Center (NCAC), in a September 2, 2025 warning, described a seller who shipped a brand-name bag, was told days later that it was fake, agreed to a return after negotiation, and received a different bag back, without the original brand box. The same warning notes that many flea-market services expect users to settle disputes between themselves, and advises sellers to ship with tracking, and, if trouble arises, to tell the operator and ask whether its authentication service, compensation scheme or investigation can help.

In almost every case the problem is how to show that what came back isn't what you sent. With the platform and with the police, having records from before shipping makes a big difference.

It isn't only swaps

Examples from news reports and public warnings:

  • A "broken" claim, then a different item comes back. In November 2024 a seller reported accepting a return over partial damage and receiving a different item.
  • Empty returns or missing accessories. Around the same time, reports spread on social media of return parcels that were empty or held a different item. In the NCAC case, accessories such as the brand box never came back.
  • Claiming the item is fake to force a return or avoid paying. NCAC has also described a buyer who, after a return was refused, claimed the item was fake and didn't pay (2018).
  • Edited "damage" photos. On March 25, 2026, Mercari prohibited using edited images that don't reflect the facts in transaction messages or messages to support. Its example is creating an image that makes an unbroken item look broken and sending it.

This isn't common. In Mercari's transparency report for the first half of 2026 (August 3, 2026), the rate of transaction inquiries was 0.35% and the rate of encountering fraudulent transactions was 0.0057%. NCAC still received 4,855 consultations about flea-market services in fiscal 2025. Don't treat buyers as suspects; just keep records, especially for expensive items.

Return rules on Mercari, Yahoo! Flea Market and Rakuma

Mercari's return process

Mercari's help page on returns describes this flow:

  1. Seller and buyer agree to the return notes.
  2. The seller requests a cancellation, and the buyer reviews and agrees.
  3. The buyer ships the item back. For transactions shipped with らくらく, ゆうゆう or エコメルカリ便, the anonymous return service is available; otherwise the buyer uses a tracked method and shares the tracking number in the transaction messages.
  4. The seller receives the item and taps "returned item received" (返送された商品を受け取った), which completes the cancellation and refunds the buyer.

The key is the order: the refund completes only when the seller confirms receipt. Mercari's seller guidelines say mutual cancellations should be completed after the returned item arrives, and completing a cancellation before the return arrives excludes you from full compensation.

For problems with an item returned to the seller, when a Mercari shipping service was used, support investigates delivery and the item's condition and tells you whether compensation applies. It asks for images showing the damage or problem, sending the actual item to the returns inspection center (Mercari announced this center on November 25, 2024 to collect swapped and counterfeit items and compare them with listing images and descriptions), and identity verification. Mercari also launched its own authentication center in September 2025 to deter counterfeit and swap fraud. The anonymous return service (rolled out from March 2, 2026) says accounts may be restricted if, for example, the size or weight of the return differs greatly from the original shipment.

Mercari's Full Compensation Support Program

Since July 1, 2025, Mercari has run a Full Compensation Support Program. Sellers are covered for their sales profit; buyers for the amount paid (excluding coupon discounts), with no upper limit; packing materials and fees aren't covered. All five conditions must be met:

  1. App-based ID verification (eKYC) completed
  2. Shipped with a Mercari shipping service (メルカリ便)
  3. Contacted support within 14 days from the day after delivery
  4. Followed the seller (or buyer) guidelines
  5. Followed the rules and terms of use, including in past transactions

The program page doesn't list every type of trouble it covers; whether a swapped return is compensated is decided by support. Don't assume you'll be covered; meet the conditions and contact support early. The seller guidelines also exclude listings whose details can't be confirmed from the description or images, and shipments not made with a Mercari shipping service.

Yahoo! Flea Market and Rakuma

  • Yahoo! Flea Market asks the parties to agree return details in the transaction messages. Its おてがる配送 shipping service can't be used for returns, so the parties exchange addresses in the messages and the buyer ships by any method, ideally tracked. It suggests shipping returns after the transaction is canceled, but leaves the order to the parties, so if you're worried about a swap, you can propose confirming the item before canceling. It doesn't handle loss or damage on the return trip. It lists "swapping the item and returning it" (商品をすり替えて返品すること) among buyer behavior subject to warnings or suspension, while its guidelines also require sellers to negotiate returns or refunds for defects they didn't disclose, and prohibit "no returns" wording.
  • Rakuma recommends tracked shipping for returns, doesn't allow anonymous shipping or addresses other than the registered one for returns, and asks buyers to keep receipts until the cancellation completes. The seller files the cancellation after checking the returned item. Transaction messages close after cancellation, so finish any messages first.

Conditions differ by service and change over time; check the latest help pages.

When listing

  • Photograph the item you actually have, from many angles. Mercari's seller guidelines ask for details, scratches and stains, accessories and packaging, not just an overall shot. Listing photos record the item's condition at listing, so also screenshot the listing in case it becomes unavailable later.
  • Decide how to handle model and serial numbers. Mercari's guides suggest clear close-ups of serial numbers for brand wallets and bags, and putting the IMEI or serial number in the description for smartphones. Showing only part of the number lets you confirm a returned item against the full number only you know. Either way, keep a photo where the whole number is readable.
  • Describe flaws honestly and specifically, such as "two small scratches on the screen". Unmentioned flaws are where disputes start.
  • Don't write "no returns". Mercari prohibits saying you won't accept returns even if there's a problem, citing "返品不可" (no returns), "ノークレーム" (no claims) and "3N" as examples, with no exception for preventing swaps; violations can lead to canceled transactions, deleted listings or account restrictions. If you want to signal you're prepared, write something like "I record the serial number and condition in photos and video before shipping."
  • Meet the compensation conditions in advance: complete eKYC and choose a Mercari shipping service.

What to record before shipping (checklist)

On shipping day, just before packing, record:

  1. The whole item: every side, inside and out.
  2. Model and serial number close-ups: engravings, labels, warranty cards; for phones and consoles, the number shown in settings.
  3. Close-ups of marks unique to that item: small scratches, stains, fading, loose stitching. For items without serial numbers, these identify the unit.
  4. Accessories, box and warranty: all together, then one by one.
  5. A video of it working: power on and main functions.
  6. A packing video: show the serial number and unique marks, wrap, box, seal and label, in one continuous take.
  7. The weight of the packed box, photographed on a scale.
  8. Shipping proof: receipt, label copy, tracking number, shipping notification.
  9. Transaction messages: screenshots of what you said about the condition and what was agreed. Mercari transaction messages close 2 weeks after the last message.

Tips: shoot wide-and-close pairs; get close enough that numbers are readable; put a note with the date and item ID next to the item (never the buyer's name or address); don't stop the packing video; don't edit originals; and keep the original files in two places.

RecordWhat it showsLimits
Whole-item photosAppearance and condition before shippingHard to tell apart from another unit of the same model
Serial number close-upsStrong identification of the unitSome items have no number; doesn't show if only the number plate was swapped
Unique marksIdentifies units without numbersSimilar marks can be hard to distinguish
Packing videoThat item went into the box and was sealedSays nothing about after the box was opened
Box weightComparison with the returned boxPacking materials change the weight; small differences prove little
Shipping proofWhen and what parcel you sentNot what was inside
Third-party timestamp (e.g., a certificate)The photo file existed by that time and hasn't changedDoesn't show when it was taken or that the pictured item was shipped; costs money

Fixing the photos to "before shipping"

If a swap is disputed, people may ask whether your "before shipping" photos really were taken before shipping. The date and time a phone records can be changed later in iPhone Photos or Google Photos, so on its own it can be weak (see how to prove when a photo was taken).

It helps to separate "no later than" from "no earlier than":

  • To show the photo existed no later than shipping, leave a dated record outside your phone: send the photos to another address of yours or a family member that day, keep them in the listing, or fix the file with a third-party timestamp (RFC 3161), which proves the file existed at that time and hasn't changed since. A timestamp from before the parcel was accepted supports "this photo existed before shipping".
  • To show it was taken no earlier than that day, include the dated note in the shot.

None of these show that the pictured item actually went into that box; that's what the uninterrupted packing video is for.

When a buyer asks for a return

When a buyer says the item is fake, not as described or broken, before agreeing:

  1. Ask for specifics and photos: close-ups of the problem, the whole item, and the box and packing as received.
  2. Compare with your own records for the same spots.
  3. Reply calmly with facts, for example "I recorded the serial number and condition before shipping." Damage in transit happens without anyone being dishonest.
  4. If talking doesn't resolve it, contact support. Mercari says that when parties can't resolve things, contacting it within 14 days of arrival lets it investigate whether compensation applies.

If you accept the return, follow the official flow and screenshot what was agreed (reason, shipping method, who pays postage). Mercari's help also describes alternatives: with support's help, refunding part of the sales profit and completing the transaction, or canceling by mutual agreement without the item being sent back. For expensive items, asking support which route to take is an option. If you don't accept a buyer's cancellation request, choosing "do not agree" (同意しない) means it doesn't go through. Note that returns for the buyer's own reasons ("not what I imagined", "no longer needed") are prohibited on Mercari unless both sides agree; undisclosed flaws are different. When unsure, ask support.

When the buyer sends "damage" photos

  • Save the images as received, noting who sent them, when and where.
  • Compare the same spots with your own photos: position, shape and size of marks, accessories, serial number.
  • Edited images are prohibited on Mercari. Since March 25, 2026, using edited images that don't reflect the facts in messages or to support (such as making an unbroken item look broken) is prohibited. Images in transaction messages may also show an "AI情報" (AI information) label when they may have been generated or edited with AI. The label is for reference only and isn't treated as a violation by itself; Mercari's help suggests asking for unedited photos or photos from another angle when you see it. (Up to 4 photos per message and 16 per person per transaction can be sent.)
  • You can check the image for signs of editing: see how to tell if a photo is edited, or run one free PEA check in English. Images sent through apps are usually resized and recompressed, so no method can say for sure that a photo was or wasn't edited. Don't accuse anyone on the strength of a tool result alone.
  • If you can't tell, send the photos to support; Mercari's process includes sending the item to the inspection center.

When the return arrives

Don't open it straight away. Record in this order:

  1. Photograph the unopened box: label, every side, the seal, dents or tears.
  2. Weigh it on a scale and compare with your shipping weight.
  3. Start filming, then open it. From the label to cutting the seal, taking the item out and showing the serial number and unique marks, in one continuous video.
  4. Compare with your records: serial number, unique marks, accessories, box.
  5. If everything matches, complete the return as the app describes (on Mercari, tap "returned item received").

If something is wrong:

  • Don't use, repair or throw away the item. Keep everything as received, including box, packing and label; support may ask you to send it to the inspection center.
  • Contact support before completing the return. On Mercari, tapping "returned item received" completes the cancellation and refunds the buyer, so contact support first and follow its instructions. Support may complete or cancel transactions left too long, so contact it the same day. On Rakuma, too, the seller cancels after checking the returned item.
  • Save the transaction messages; they become unavailable after cancellation or a set period.

If the item was swapped: platform, police and other help

  • Platform support first. On Mercari, choose the transaction and the issue in the help center and use the contact link at the bottom of the guide (login required), as "a problem with an item returned from the buyer to the seller", with images attached and a specific description. Follow support's instructions on the inspection center and identity verification. On Yahoo! Flea Market and Rakuma, use the contact form in each help center.
  • Police. Sending back a different item to recover payment can, depending on the facts, amount to fraud (Penal Code Article 246, which carries imprisonment of up to 10 years; whether it applies is decided by investigators and courts). The National Police Agency advises taking materials such as the listing URL and images to your local police station, and calling ahead to arrange the time and what to bring. You can also call #9110, the police consultation line (in an emergency, 110). Bring the listing page, transaction ID and the other user's name, saved messages, pre-shipping photos and video, shipping and return receipts, the unboxing video, the item (or photos of it), and your exchanges with support. On July 9, 2026, Mercari signed an information-sharing agreement with the National Police Agency covering transactions it judges likely to be fraudulent.
  • Consumer hotline 188 (in Japanese) or Houterasu's Multilingual Information Service, 0570-078377 (weekdays 9:00–17:00, English and nine other languages; call charges apply), and a lawyer if you want to claim damages (Civil Code Article 709).

Don'ts

  • Don't name and shame the buyer on social media or in reviews without solid evidence; it can lead to defamation and other trouble, and Mercari prohibits abusive review comments and exposing personal information.
  • Don't use, repair or discard the returned item before support or the police have seen it.
  • Don't complete the return before checking.
  • Don't edit your pre-shipping photos or video before sharing them; keep originals and edit copies.
  • Don't deal or refund outside the app; Mercari prohibits steering to other services, and you may lose compensation.

What PEA can and can't do

PEA (Professional Evidence Authenticator), from Lumina Spark in Japan, checks images for signs of AI generation or editing with several independent analyses and shows a grade from 1 to 10. It does not authenticate whether a returned item is genuine.

Start with the free steps: photos and video before shipping, original files, tracked shipping with a Mercari shipping service. A PEA certificate is an extra step for the most important photos of expensive items.

  • Fix your pre-shipping photos in a form others can verify. A check records the file's SHA-256 hash and seals it with an Ed25519 digital signature and a third-party RFC 3161 timestamp. The timestamp is the time of the check, so checking on shipping day, before you ship, supports "this photo existed before shipping".
  • Turn it into a certificate within 7 days (¥1,000 per image, charged in yen, international cards accepted). Support, a lawyer or anyone you show it to can check the issue time, file hash and timestamp by certificate number on PEA's public verification page.
  • Pick one or a few photos that identify the item, such as the serial number or a unique mark. Free checks are limited per day; the Plus plan covers more.
  • Keep the exact file you checked; re-saving or cropping changes the hash.
  • Photos only (JPEG, PNG, HEIC, up to 25 MB); keep packing and unboxing videos as original files.

PEA can't prove that a returned item differs from what you sent, who swapped it, that the pictured item was actually shipped, or when a photo was taken. It shows that the file existed at the time of the check and hasn't changed since, plus the analysis results. The timestamp is not one accredited by Japan's Minister for Internal Affairs and Communications, and we can't promise how support, the police or a court will weigh it. Use it with your packing video, shipping proof and unboxing video. If you buy on Mercari, see also Mercari Japan: is that listing photo AI?. The account and certificate screens are in Japanese; browser translation works on them.

This article is general information about Japan, not legal advice.

Frequently asked questions

What is return fraud on Mercari Japan?

"Return fraud" isn't an official Mercari term, but it's used for abusing the return process to make a seller lose out. Reports and public warnings describe buyers claiming an item was broken or fake, getting a return approved, and sending back something else (a swap), or returning an empty box or keeping the accessories. Since March 2026, Mercari has prohibited using edited images that don't reflect the facts, such as making an unbroken item look broken, in transaction messages or messages to support.

The buyer's damage photos look edited or AI-generated. What should I do?

Save the images as received and compare the same spots with your pre-shipping photos: position and shape of marks, serial number, accessories. Mercari's transaction messages may show an "AI情報" label on images that may have been generated or edited with AI, and its help suggests asking for unedited photos or another angle when it appears. Don't accuse the buyer on a label or tool result alone; if you can't tell, send the photos to support.

What should I photograph before shipping to protect against swaps?

Besides overall photos, take close-ups of the model and serial number, marks unique to that item, and the accessories. Then film the packing in one continuous take, from showing the number to sealing the box and attaching the label, and keep the box weight and the shipping receipt. Don't edit the original files, and keep them in two or more places.

What if the returned item was swapped?

Keep everything as received, including the box and label, and don't use or discard the item. Film the unboxing, compare it with your pre-shipping records, and contact support before tapping "returned item received", which completes the cancellation. Mercari may ask for images, sending the item to its inspection center, and identity verification. If it isn't resolved, you can talk to the police (#9110) or a consumer center (188).

Is return fraud covered by compensation?

Mercari's Full Compensation Support Program (since July 1, 2025) covers sellers' sales profit, but only if all conditions are met: eKYC, a Mercari shipping service, contacting support within 14 days from the day after delivery, and following the guidelines and terms. Support decides whether to compensate after reviewing the case. For Yahoo! Flea Market and Rakuma, check each service's help pages.

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