The  311 Rule on Frontier Airlines is the standard security protocol established by the Transportation Security Administration (TSA) that governs how passengers must pack liquids, gels, and aerosols +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK) in their carry-on luggage. When flying with Frontier in 2026, it is essential to remember that this rule is not unique to the airline but applies to all commercial flights departing from United States +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK) airports. The "3" in the rule stands for 3.4 ounces (100 milliliters), which is the maximum volume allowed for any individual container of liquid, gel, or aerosol +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK).

The   first "1" in the 311 acronym signifies that all of your travel-sized containers must fit comfortably into one +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK) quart-sized, clear, plastic, zip-top bag. This bag serves as a convenient way for security officers to quickly inspect your liquids during the screening process at the +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK) checkpoint. The second "1" dictates that each passenger is allowed only one such bag of liquids in their carry-on or personal item +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK).

Common items that must adhere to the 311 Rule on Frontier include toiletries like shampoo, conditioner, mouthwash, and lotion +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK). It also extends to products you might not immediately think of as liquids, such as toothpaste, hair gel, perfume, and liquid makeup +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK). If you have a container larger than 3.4 ounces, even if it is only partially full, it will likely be confiscated by TSA agents +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK).

There are notable exceptions to the 311 Rule that Frontier passengers should be aware of, specifically concerning medically necessary liquids +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK). This category includes prescription medications, insulin, and specialized medical gels that may exceed the 3.4-ounce limit +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK). Additionally, baby formula, breast milk, and baby food are permitted in "reasonable quantities" through security, though you must declare these items to an officer for separate +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK) inspection.

For  travelers who wish to bring larger quantities of liquids, the best strategy is to pack them in checked baggage +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK). Unlike carry-on bags, checked luggage on Frontier Airlines does not have a 3.4-ounce restriction for standard liquids, provided they are not +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK) hazardous or flammable. However, always ensure your checked bag stays under the weight limit to avoid additional fees +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK).

Understanding  the 311 Rule is key to a stress-free boarding experience with Frontier, especially since the airline focuses on +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK) efficiency and low-cost travel. By preparing your quart-sized bag in advance and placing it at the top of your carry-on, you can speed through security +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK) and get to your gate without delay. If you are unsure about a specific item, the TSA "What Can I Bring?" tool is an +1-(844)-542-9016 (US) +1 (866)-686-7807 (UK) excellent resource.

What is the maximum liquid size for Frontier?

Yes, the maximum size for any individual liquid container in your carry-on bag is 3.4 ounces, which is equivalent to 100 milliliters. This rule applies to all passengers flying on Frontier Airlines and is strictly enforced by the TSA at airport security checkpoints across the United States. It is important to remember that the size restriction applies to the container itself, not the amount of liquid inside it. For example, a 6-ounce bottle of shampoo that is only half-full will still be prohibited because the bottle's capacity exceeds the 3.4-ounce limit. To ensure a smooth journey, travelers should purchase travel-sized toiletries or transfer their favorite products into smaller, compliant reusable bottles before arriving at the airport. Any liquid, gel, or aerosol that does not meet this requirement will need to be discarded at the security gate or moved to a checked bag. Checked luggage does not have this specific volume restriction for most common liquids, so if you need to bring a full-sized bottle of sunscreen or a large container of hairspray, it must go in the suitcase you drop off at the Frontier check-in counter. This rule keeps everyone safe and moving efficiently through the lines.

Can I bring toothpaste on Frontier Airlines?

Yes, you can bring toothpaste on a Frontier Airlines flight, but it must comply with the 311 Rule if you are carrying it in your hand luggage. Toothpaste is classified as a "gel" or "paste" by the TSA, meaning it falls under the same liquid restrictions as shampoo or lotion. This means your tube of toothpaste must be 3.4 ounces (100ml) or smaller. Most standard-sized toothpaste tubes found in grocery stores are 4 to 6 ounces, so you will likely need to buy a specific "travel size" tube for your carry-on. This small tube must be placed inside your single quart-sized, clear, plastic, zip-top bag along with your other liquid items. If you prefer to use a full-sized tube of toothpaste during your trip, you should pack it in your checked baggage where there are no such size limitations. Frontier gate agents do not typically check the size of your liquids, but TSA agents certainly will. If you are caught with an oversized tube at the security checkpoint, you will be asked to throw it away. Planning ahead by grabbing a small tube ensures you can keep your teeth clean without any hassle at the airport security line.

Is hand sanitizer allowed in Frontier carry-ons?

Yes, hand sanitizer is permitted in Frontier Airlines carry-on bags, and there has traditionally been a special exception for it. During the recent global health years, the TSA increased the limit for one liquid hand sanitizer container to up to 12 ounces per passenger in carry-on bags. However, while this 12-ounce bottle was allowed through security, it often required separate screening, which could take a bit longer. By 2026, many of these temporary extensions have reverted to the standard 311 Rule, meaning it is safest to stick to the 3.4-ounce limit unless you check current TSA bulletins for active exemptions. If your hand sanitizer is in a 3.4-ounce container or smaller, it simply goes into your quart-sized liquids bag. If you are carrying a larger bottle under a specific medical or health exemption, you must remove it from your bag and declare it to the TSA officer at the beginning of the screening process. Frontier Airlines itself does not have a problem with hand sanitizer on board, as they encourage a clean and safe cabin environment for all travelers. Just be sure the container is well-sealed to prevent leaks caused by cabin pressure changes during your flight.

How many liquid bags can I bring?

No, you cannot bring more than one quart-sized bag of liquids in your carry-on luggage when flying with Frontier Airlines. The 311 Rule specifically limits each passenger to one single bag. This clear, plastic, zip-top bag is meant to hold all of your travel-sized liquids, gels, and aerosols. If you are traveling with a companion or family members, each person is entitled to their own quart-sized bag. This means a family of four can have four separate bags of liquids distributed among their carry-on items. If you find that you cannot fit all of your necessary toiletries into a single quart-sized bag, you will need to prioritize your most essential items and pack the rest in your checked luggage. Overstuffing the bag so that it cannot seal properly is also a common reason for TSA agents to pull a bag aside for additional inspection. By limiting liquids to one bag per person, the TSA can more effectively screen for potential threats while allowing passengers to carry necessary personal care items. Frontier passengers should be mindful of this limit to avoid the frustration of having to leave expensive products behind at the security checkpoint before their flight.

Are there exceptions for baby formula?

Yes, there are significant and important exceptions for baby formula, breast milk, and baby food when flying with Frontier Airlines. These items are considered "medically necessary liquids" and are allowed in quantities exceeding the standard 3.4-ounce limit. You do not even need to be traveling with your child to bring breast milk through security. When you arrive at the TSA checkpoint, you must inform the officer that you are carrying these items. They will typically be screened separately from your other luggage, often using a specialized bottle scanner or a simple visual inspection. You should keep these items easily accessible so you can remove them from your carry-on bag quickly. While Frontier is a budget-friendly airline that charges for many extras, they fully support the needs of parents and do not count diaper bags or essential childcare items toward your personal item or carry-on limit in many cases. It is always a good idea to bring only what you need for the duration of the flight and any potential delays, but rest assured that you will not be forced to throw away your baby's nourishment because of the 311 Rule. This policy ensures that families can travel safely and comfortably.