Liquid Rules at Korean, Japanese, and Taiwanese Airports: 100ml Containers, One Zip Bag, and Packing Winter Skincare Minis
Incheon, Narita, and Taoyuan share the same basic numbers for liquids and gels: 100ml or less per container, carried in a zip bag of 1L or less, one bag per person. What differs is the zip bag's width and length. Korea specifies 20.5cm by 20.5cm or 15cm by 25cm, Japan requires the width plus length to total no more than 40cm, and Taiwan sets each side at 20cm by 20cm. That means a zip bag bought in one country can fall outside the rules if you carry it through another.
Winter trips tend to add items like hand cream and heavy moisturizing cream, so the 1L zip bag fills up fast, and swapping products into mini containers has to be finished before you get to the airport.
Incheon Airport: 100ml Containers, One Zip Bag
At Incheon International Airport, liquids, gels, and sprays must each be packed in individual containers of 100ml (g) or less. If you're carrying multiple containers, all of them must fit inside a single transparent zip bag of 1L or less, completely sealed. The zip bag comes in two sizes, 20.5cm by 20.5cm or 15cm by 25cm, and each passenger is allowed only one bag.
The items covered by this rule are broader than you might expect. Beyond gels like shampoo, toothpaste, and hair gel, semi-solid foods such as gochujang and doenjang paste are also included. On the other hand, solid-form products like lip balm sticks or solid shampoo bars aren't classified as liquids or gels, so they can be carried outside the zip bag.
The full list of covered items and exceptions is available at the Incheon International Airport restricted items guide.
Japan: Zip Bag with Width Plus Length of 40cm
Under rules set by Japan's Ministry of Land, Infrastructure, Transport and Tourism, each container must be 100ml or less, packed into a single resealable transparent zip bag of 1L or less, the same as in Korea. The difference is that Japan defines the zip bag size as width plus length totaling no more than 40cm.
This difference matters in practice. The 20.5cm by 20.5cm zip bag commonly used in Korea has a combined width and length of 41cm, 1cm over Japan's limit. The 15cm by 25cm bag, however, adds up to exactly 40cm, so it fits Japan's rule as is.
Narita Airport provides this guidance in Korean as well, and it can be checked directly at the Narita Airport guide on restrictions for bringing liquids on international flights.
Taiwan's Taoyuan: Zip Bag with Each Side at 20cm
Taiwan shares the same numbers as Korea and Japan: 100ml (c.c.) or less per container, one transparent zip bag of 1L or less per person. The difference is that Taiwan sets each side of the zip bag at 20cm by 20cm.
The 20.5cm by 20.5cm zip bag used in Korea has sides that are 0.5cm too large, putting it outside Taiwan's rule. The 15cm by 25cm bag also exceeds Taiwan's 20cm limit, since one side measures 25cm. If your itinerary includes Taiwan, it's safer to prepare a separate zip bag of 20cm by 20cm or smaller.
This is laid out in the guidance from the Aviation Police Bureau, under Taiwan's Ministry of the Interior's National Police Agency, on control measures for liquids, gels, and sprays.
Comparing Zip Bag Specs Across the Three Airports
| Airport/Region | Limit per Container | Zip Bag Capacity | Zip Bag Dimensions | Bags per Person |
|---|---|---|---|---|
| Incheon, Korea | 100ml (g) or less | 1L or less | 20.5 x 20.5cm or 15 x 25cm | 1 |
| Japan (MLIT) | 100ml or less | 1L or less | Width plus length of 40cm or less | 1 |
| Taoyuan, Taiwan | 100ml (c.c.) or less | 1L or less | 20 x 20cm | 1 |
All three airports agree on 100ml per container, 1L per zip bag, and one bag per person, but they measure the zip bag's dimensions differently. It's safer not to assume that a zip bag bought in one country will pass inspection in another.
Duty Free Liquids in STEB Bags Have No Volume Limit
Liquor, cosmetics, and other liquids purchased at airport duty free shops are handled separately from the standard zip bag rule. As long as they're sealed in the STEB (Security Tamper Evident Bag) provided at purchase, with the receipt enclosed inside the bag, they can be carried onboard regardless of volume.
That said, the bag must stay sealed until you board your final destination flight, and if a connecting country's security rules differ, the item could be confiscated or you may be asked to give it up at the connecting airport's security checkpoint. If your itinerary involves buying duty free goods at Incheon and connecting through Narita or Taoyuan, it's safer to check this with your airline or travel agency in advance.
This is explained in the Ministry of Government Legislation's Easy Guide to Law, on purchasing duty free goods.
How to Fit Winter Skincare Minis into the 1L Bag
Winter trips tend to add items like hand cream, heavy moisturizing cream, liquid lip balm, and body oil that you might not usually pack, so you need to switch all of them into containers of 100ml or less and keep the combined volume under 1L to fit everything in a single zip bag.
Olive Young's Minis travel set includes 50ml of moisturizing shampoo, 30ml of conditioner, 50ml of body wash, and 30ml of cleansing foam, adding up to just 160ml total for all four, only about 16% of the zip bag's capacity. It's priced at 9,900 won, discounted from 11,900 won. You can check the set's contents at the Olive Young Minis travel set page.
If you want to bring along your regular toner and cream by decanting them, the Daiso Mall 4 piece travel cosmetic container set (two 10g cream jars, two 30ml toner bottles, including a spatula and pouch, priced at 1,000 won) lets you free up remaining zip bag space for sunscreen or cleansing oil.
Switching lip balm or sunscreen to a solid stick form frees up even more zip bag capacity, leaving room for the extra liquid items that winter travel tends to add.
Sources: Incheon International Airport, restricted items guide
Sources: Narita International Airport, guide on restrictions for liquids brought on international flights
Sources: Ministry of Government Legislation, Easy Guide to Law, on purchasing duty free goods
Sources: Olive Young, Minis travel set