Airport security can feel like an obstacle course of unwritten rules, and nothing derails a smooth departure faster than having a favourite bottle of perfume or a carefully packed moisturiser confiscated at the checkpoint. The liquid restrictions that apply to carry-on baggage are among the most widely misunderstood aspects of modern air travel, yet the core rule is genuinely simple once you know it. This guide covers everything you need to understand about liquid allowances on planes, from the fundamental 100ml limit to the exemptions that most travellers do not realise they qualify for.

Whether you are heading off on a short weekend trip or a long-haul journey, getting your liquids right before you reach the scanner saves time, reduces stress, and means you arrive at your gate with your toiletry bag intact. Keep reading for a complete, practical breakdown of the rules — and how to pack around them.

Before you focus on what to pack, make sure your journey starts smoothly. Arrange your airport transfer to Singapore Changi in advance and book your flights through Traveloka for a seamless start to every trip.

The internationally recognised standard for carry-on liquids is commonly referred to as the 3-1-1 rule. Each individual liquid container must hold no more than 100 millilitres — note that a 200ml bottle that is only half full still does not comply, because the container itself exceeds the limit. All your liquid containers must fit together into a single transparent, resealable plastic bag with a total capacity of no more than one litre. Finally, each passenger is permitted to carry one such bag through the security checkpoint.

This rule was introduced following security recommendations adopted by aviation authorities around the world, and it applies at Changi Airport and most major international airports regardless of which airline you are flying. The rationale is straightforward: certain liquids can be used as components in improvised explosive devices, and limiting the volume any individual passenger carries significantly reduces that risk. While the restriction can feel inconvenient, it is one of the most consistently enforced measures in aviation security worldwide.

The category of liquids in aviation security is broader than most travellers initially assume. It includes not just water, juice, and beverages, but also gels, pastes, creams, and aerosols. Toothpaste, hair gel, sunscreen, moisturiser, foundation, mascara, and even peanut butter all fall under the liquid rule because of their consistency. Aerosol cans — including deodorant sprays and dry shampoo — are subject to the same 100ml per container limit and must fit within your transparent bag.

Soups, sauces, jams, and other food items with a pourable or spreadable consistency are also classified as liquids and subject to the same restriction in your carry-on. If you are travelling with any artisan foodstuffs, pickles, or liquid-based condiments as gifts, pack them in your checked luggage to avoid losing them at the checkpoint. Solid foods, hard cheeses, and items that hold their shape at room temperature are generally not subject to liquid restrictions. When in doubt, the safest approach is to pack the item in checked baggage.

A small number of liquid substances are prohibited from both cabin and hold regardless of volume, primarily for safety reasons. These include liquid explosives, flammable liquids beyond specified thresholds, and certain industrial chemicals. Most travellers will never encounter these restrictions in normal packing, but they are worth being aware of if you travel frequently for work and carry professional materials. Airlines provide detailed guidance on their websites, and Changi Airport's security page lists the full prohibited items register.

Several important categories of liquid are exempt from the 100ml rule, and knowing them can make a meaningful difference to how you pack. The exemptions recognised at most international airports, including Changi, cover the following situations.

Prescription medications in liquid form — including insulin, liquid antibiotics, and eye drops — are exempt from the 100ml limit when accompanied by appropriate documentation. A doctor's letter, prescription printout, or the original pharmacy packaging with your name on the label is typically sufficient. You will be asked to declare these items separately at the security checkpoint and present them for inspection. Topical creams and gels used for medical purposes fall under the same exemption with documentation, so speak to your doctor before travel if you rely on them.

Parents travelling with infants are permitted to carry sufficient quantities of baby milk, formula, and pureed baby food for the duration of the journey without being subject to the 100ml container limit. Security officers may ask you to open and taste the items to confirm their contents, which is standard procedure rather than cause for concern. Breast milk is also exempt and can be carried in quantities appropriate to the journey, even if the passenger is travelling without the infant. It is always advisable to check the specific policy of your departure airport if you are travelling internationally through multiple security checkpoints.

Liquids purchased from duty-free shops inside the airport security zone — including perfumes, wines, spirits, and cosmetics — are exempt from the 100ml rule provided they are sealed in a tamper-evident bag issued by the retailer at the point of purchase. The receipt should remain inside the bag and visible through the packaging. Problems typically arise when passengers transfer through a second airport and must clear security again, so check the transit rules for any connection airports on your itinerary in advance. Some countries do not accept duty-free bags from other airports as proof of secure purchase.

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With a little preparation, the 100ml rule becomes far less restrictive than it first appears. The key is to think ahead about which liquid products you genuinely need in your cabin bag versus which can safely travel in your checked luggage or be purchased at your destination.

Many major cosmetic and personal care brands sell 50ml and 75ml versions of their standard products specifically for travellers. Investing in a set of refillable travel bottles lets you decant the exact products you prefer into compliant containers and reuse them across every trip. Silicone bottles with flip-cap lids tend to be the most leak-resistant option and can be purchased cheaply from most luggage and pharmacy retailers. Label each bottle clearly so security officers — and you — can quickly identify the contents.

The beauty and personal care industry has developed an extensive range of solid alternatives to traditionally liquid products. Solid shampoo bars, conditioner bars, soap, and even solid sunscreen sticks eliminate the liquid restriction entirely while often being more concentrated and longer-lasting than their bottled counterparts. Solid toothpaste tablets are another option worth exploring for frequent fliers. Switching even a few products to solid form can free up significant space in your one-litre bag and reduce the chance of any item being flagged at the checkpoint.

Place your transparent liquids bag in an easy-access outer pocket of your carry-on so you can pull it out at the security conveyor belt quickly and without unpacking your entire bag. Security screening is significantly faster when passengers are prepared, and it reduces stress for you and the travellers behind you. Double-check your bag the evening before departure rather than at the airport — discovering a full-size shampoo bottle at the checkpoint is a stressful and entirely avoidable experience. A calm, well-organised approach to security means you reach your gate relaxed and ready to fly.

Now that you know exactly what you can and cannot bring through security, the only thing left to do is plan the trip itself. Traveloka is Southeast Asia's leading travel platform, trusted by over 100 million users, and it brings together everything you need in a single app — flights, hotels, activities, airport transfers, car rental, eSIM, and travel insurance.

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