如果去年12月已經完成Visit Japan Web（VJW）的申報，而且在這段時間內航班、住宿、同行家人等資訊都沒有任何變更，那麼在隔年一月底前往日本時，原本生成的QR Code通常仍然有效。VJW的設計初衷就是讓旅客能夠在出發前就完成入境申報，並在抵達時直接出示QR Code通關，因此只要行程沒有變動，就不必每次都重新申請新的申報。

不過，即便QR Code仍然有效，建議旅客在出發前仍要重新登入VJW系統，並確認該次行程的QR Code能否順利顯示。因為有些人可能會因為手機更新、瀏覽器快取或帳號狀態等因素，導致QR Code無法順利開啟，若到了機場才發現問題，可能會增加通關壓力。為避免這種情況，最好提前確認，並在需要時重新整理或重新生成QR Code，確保能順利出示。

至於有效性方面，只要在系統中登錄的「預定入境日」前後，該次行程的QR Code 通常都可以使用，不會因為超過某個固定期限就立即失效。但仍然建議在出發前確認資訊是否仍然正確，尤其是航班號碼與抵達日期是否與實際行程一致。若在申報後更改航班或住宿，或同行家人名單有所變動，就必須在VJW內更新資料，否則可能在入境審查時遇到不一致的狀況，影響通關速度。

除了確認行程資訊之外，也別忘檢查護照效期。日本入境時通常要求護照在入境當天起至少還有六個月以上的有效期限，因此如果護照接近到期，最好提前換發新護照，並在VJW內更新護照資料，避免因護照效期問題而被拒絕入境。

為了更保險，也建議在出發前QR Code做備份。直接將QR Code截圖存到手機相簿，或使用VJW的「離線服務」功能下載到手機，這樣即使在機場遇到網路不穩、手機訊號差或系統當機，也能直接出示QR Code通關。這種做法雖然看似多餘，但在實際旅途中常常能省下不少時間與麻煩。

最後提醒，VJW雖然方便，但仍然是一個需要維持資訊一致性的系統。建議在出發前花幾分鐘確認所有資料，尤其是航班、住宿、同行家人與護照資訊是否完全正確，這樣就能在抵達日本時順利快速通關，讓旅程從一開始就順暢無阻。

If you completed your Visit Japan Web (VJW) declaration last December and none of the information has changed—such as your flight, accommodation, or traveling companions—then the QR code generated at that time will usually still be valid when you travel to Japan at the end of January. The purpose of VJW is to allow travelers to complete entry declarations before departure and simply present the QR code upon arrival, so if your itinerary remains unchanged, there is generally no need to reapply for a new declaration.

However, even if the QR code is still valid, it is recommended to log in to the VJW system again before your trip and verify that the QR code for that itinerary can be displayed properly. Some users may encounter issues due to phone updates, browser cache, or account status, which could prevent the QR code from opening smoothly. If this issue is discovered at the airport, it can cause unnecessary stress and delays. To avoid this, it is best to check in advance and, if necessary, refresh or regenerate the QR code to ensure it can be presented without problems.

Regarding validity, the QR code can generally be used as long as it is within the period around the “scheduled entry date” registered in the system. It does not expire immediately after a fixed deadline. Still, it is recommended to confirm that all information remains accurate before departure, especially whether the flight number and arrival date match your actual itinerary. If you have changed your flight, accommodation, or the list of traveling companions after registering, you must update the information in VJW; otherwise, inconsistencies may affect the speed of your entry screening.

In addition to confirming your itinerary details, do not forget to check your passport validity. Japan generally requires that passports remain valid for at least six months from the date of entry. If your passport is close to expiration, it is best to renew it in advance and update your passport information in VJW to avoid being denied entry due to passport validity issues.

For extra security, it is also recommended to back up the QR code before departure. You can take a screenshot of the QR code and save it in your phone gallery, or use VJW’s offline service to download it to your phone. This way, even if the airport has unstable internet, weak signal, or the system is temporarily unavailable, you can still present the QR code for smooth entry. Although this may seem unnecessary, in practice it can save you a lot of time and trouble during travel.

Finally, while VJW is convenient, it still requires consistent information. Take a few minutes before departure to confirm that all details—especially flight, accommodation, traveling companions, and passport information—are completely accurate. This will help ensure a smooth and fast entry process upon arrival in Japan, allowing your trip to start without any issues.