How to provide your IOSS number to Japan Post? 28 October 2025 14:50 Updated Providing your IOSS number to Japan Post ensures your shipments are handled appropriately. Link to Japan Post instructions on their website: https://www.post.japanpost.jp/int/use/ioss.html Related to IOSS Shipping Japan Post Related articles How to provide your IOSS number to FedEx? How to sell cross-border on custom platform: full API description Using the EU Customs Tariff & HS Code Tool How to provide your IOSS number to Posten Norway? Managing Returns, Discounts, and double payment of VAT in Shopify