The rule, exactly
The instrument is the operating standard for liquids, aerosols and gels, issued by the Ministry of Land, Infrastructure and Transport (국토교통부) under the Aviation Security Act, and it applies to every international departure, transfer and transit at a Korean airport:
- Every liquid, aerosol or gel must be in a container of 100 mL or less — stated as 3.4 oz or 100 g.
- You may transfer a liquid into a suitable container of 100 mL or less. The original larger container cannot pass as an ordinary cabin liquid merely because it is partly empty. An empty container over 100 mL is fine.
- All the containers go in one transparent, resealable plastic bag of at most 1 litre — 20.5 cm × 20.5 cm or 25 cm × 15 cm — and the bag must close completely.
- One bag per passenger. Not one per item, not one per hand bag.
Incheon Airport's own restricted-items page adds the one piece of good news: Korean domestic flights do not use this international 100 mL screening limit. Dangerous-goods and baggage restrictions still apply. The 100 mL rule is an international-departure rule.
Check creams, gels and other liquid products
The standard's own schedule of controlled goods is far wider than most people assume:
| Category | Named examples |
|---|---|
| Creams | Medicated creams, ointments, moisturising cream, cleansing cream |
| Lotions | Milk lotion, skin lotion, body lotion, sunscreen, toner (화장수), liquid soap |
| Cosmetics | Liquid foundation, nail polish, nail-polish remover |
| Mascara, liner and lips | Liquid mascara, liquid eyeliner, liquid lip gloss, liquid lip balm, gel-type lipstick |
| Gels | Shampoo, conditioner, treatment, hair gel, shower gel |
| Pressurised containers | Shaving foam, cleansing foam (세안폼) |
| Toothpaste and oral care | Toothpaste, mouthwash, mouth rinse |
| Perfume and sprays | Perfume, shower cologne, hairspray, facial mist |
| Foods with sauce or high liquid content | Kimchi, marinated meats, fish sauce |
| Sauces | Gochujang and doenjang, ketchup, mayonnaise |
| Syrups and jams | Honey, syrups, extracts, spreads, butter |
| Liquid-solid mixtures | Korean herbal health preparations such as the ten-ingredient herbal tonic (십전대보탕), ink, paint |
| Anything else | Any substance that stays liquid at room temperature, including anything suspected of being one |
Check each container against the cabin limit and the total bag capacity before choosing which products to carry on. A cushion compact may contain liquid or cream cosmetics; check the product rather than judging by the case. Cleansing foam can be a liquid or aerosol, depending on its packaging. A "gel" lip tint is a gel. A 200 mL toner bottle exceeds the ordinary cabin-container limit even if it is partly empty.
Check sheet masks and other liquid-soaked products before packing. Ask the airport or airline how they should be presented for screening, especially if the liquid quantity is not clear from the package.
Necessary medicines and special dietary items
Separate exemptions may apply to necessary liquid medicines, baby food and special dietary items in quantities needed for the journey. Check the departure airport’s requirements before travelling and carry supporting documents where required. Present these items separately and explain them to the screening staff.
A medicine’s prescription status does not automatically exempt every quantity or package. Keep it identifiable, allow time for additional screening and check any connecting airport’s rules as well.
Keep qualifying duty-free liquids sealed through your connection
Duty-free goods are the exception that lets a 200 mL serum into the cabin, and it is narrower than people think. The mechanism is the security tamper-evident bag (STEB, 액체류보안봉투), which only designated suppliers may issue — airside airport shops, downtown duty-free shops, and airline in-flight sales. A downtown purchase is handed over in one at the airside pickup counter, the counter “Duty-free pickup at departure” describes.
The rules that govern the bag:
- Keep the receipt inside the sealed bag and available for inspection. Follow the screening officer’s instructions.
- Nothing you did not buy at that shop may go in it. Putting your own toner in a duty-free bag voids it.
- The seal must not be broken before your final destination. Bags carry the wording "Do not open until final destination — contents may be confiscated if bag is tampered with", and a screener may act on exactly that.
Check the rules at every connecting airport before buying a large duty-free liquid. A sealed bag and receipt do not guarantee acceptance at every checkpoint, and transfer screening may impose additional conditions. Ask the retailer and airline about your itinerary before paying.
Checked baggage still has limits
The international cabin 100 mL rule does not apply to checked baggage, but that does not make every liquid unrestricted. Check the airline’s dangerous-goods guidance for the exact product, as well as baggage weight and destination import rules.
Medicinal and toiletry articles covered by the dangerous-goods allowance, including permitted aerosols, generally have a combined limit of 2 kg or 2 litres per person and a maximum of 500 g or 500 mL per article. Protect aerosol valves against accidental release. IATA’s passenger guidance explains that airlines may apply additional conditions.
A flammable industrial spray is not treated the same way as a permitted toiletry aerosol. Ask the airline if the product’s classification is unclear. Power banks must stay in cabin baggage and have separate capacity, quantity and handling requirements.
Resolve packing problems before security
Do not rely on recovering an item after surrendering it at security. Before entering the queue, check whether an oversized liquid can be packed in checked baggage or left with an available storage service. These options depend on the airport, time remaining and product restrictions.
What to do
- Pack larger liquid containers in checked baggage, subject to baggage and dangerous-goods rules. Decide this while packing, not at the lane.
- Pack the cabin liquids you need within the container and one-litre bag limits.
- Confirm the full itinerary’s duty-free liquid rules before buying a large bottle. Keep any qualifying bag sealed.
- Keep the receipt visible inside the sealed bag, not in your wallet.
- Check the rules at your connecting airport. A sealed duty-free bag does not guarantee acceptance at every checkpoint.
- Present necessary medicines separately, with any identification and supporting documents required for your journey.
