Rules for Flights in the USA
In the United States, empty metal water bottles are allowed in hand and checked baggage. TSA doesn’t establish a size, material, or weight restriction for water bottles, so you’re allowed to travel with aluminum, stainless steel, and other water bottles.
The only condition for hydro flasks to be allowed through security is that they must be completely empty of any liquids. That’s because all liquids in hand luggage have to follow the 3-1-1 rule and hydro flasks usually are too large to fit in a 1-quart bag, and their volume is above 3.4 oz / 100 ml.
Rules for Flights in Other Countries
Canada, Europe, and New Zealand
The United Kingdom, China, and India
On the United Kingdom, Chinese and Indian flights, metal water bottles aren’t mentioned specifically as allowed or banned from airplanes. But generally, they are permitted in hand and cargo baggage as long as they don’t contain any liquids.
In Australia, empty metal water bottles are allowed in cabin and cargo luggage. On domestic flights, it’s also allowed to bring water bottles containing water or other liquids, as there aren’t any liquid restrictions for cabin baggage.
Sources: For writing this article, we took information only from official sources, like airline regulators, government websites, and major airlines. If you want to confirm that our information is accurate and up to date, click on any of the links mentioned above. We linked out to where we found this information for each country.
Disclaimer: The final decision of whether you can bring metal water bottles on planes always rests on the security officer. Some airlines also have additional rules that may be different.
Frequently Asked Questions About Bringing Metal Hydro Flasks on Planes
Can I take a hydro flask with frozen water through security?
In theory, you can take a hydro flask with frozen water through airport security with certain restrictions. TSA allows completely frozen liquids through airport security as long as they are hard solid, don’t have any liquid, and aren’t in a slushy state. However, due to the nature of a metal hydro flask, it might be difficult for agents to visually confirm if there is any liquid in the bottom of the bottle. As a result, your hydro flask could get confiscated at airport security.
In addition, freezing a hydro flask is not recommended, as it might damage the bottle’s seal and crack the insulated walls. Although it’s theoretically possible to travel with a frozen hydro flask, it’s not recommended. Instead, do it with a disposable water bottle, which you aren’t afraid to throw out if asked to.
Do I need to take out hydro flasks when going through security?
Generally, you don’t need to take out hydro flasks when going through security in the United States. TSA asks to take out only liquids, large electronics, and large amounts of powder.
However, your hydro flask must be completely empty. When you’re going through security, if the hydro flask has any liquid in it -even if the bottle isn’t entirely full, the security guards will take it out of your bag and ask you to dispose of it.
Does my hydro flask need to be completely empty when going through security?
Yes, your hydro flask needs to be completely empty when going through airport security. TSA allows for hydro flasks to go through security without any restrictions on the size of the container. However, only empty bottles are allowed through security. If your hydro flask is partially filled, it will be confiscated at the security checkpoint. The only way your water bottle is allowed through the security checkpoint with liquid is that the container is under 3.4 ounces / 100 milliliters and it’s packed together with other liquids in a 1-quart resealable bag.
Is it better to pack metal water bottles in hand or checked luggage?
It doesn’t really matter where you pack your hydro flask because they’re allowed both in hand and checked baggage. One advantage to packing it in your carry-on is that you can refill it at the airport with tap water. That way you can avoid buying expensive water bottles at the airport or during the flight.
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Can a hydro flask or thermos explode on a plane?
No, hydro flasks and thermos will not explode on a plane by themselves. It’s true the changes in cabin pressure might affect your hydro flask or thermos if they have any liquids in them, and suddenly popping them open might get a tiny amount of liquid out with pressure (particularly on flasks with an integrated straw). But you can easily avoid this by opening the bottle cap slowly, to release the accumulated pressure, before drinking from them.
Can I fill up my hydro flask at the airport or airplane?
Yes, you can fill up your hydro flask at the airport with certain restrictions. When going through airport security, your hydro flask must be empty. But, after the checkpoint, you’re allowed to fill up your hydro flask with tap water and take it on the plane.
Can I bring a thermos, a Yeti cup, or a Tumbler on a plane?
You’re allowed to bring thermos cups, Yeti cups, and tumblers on a plane in your hand or checked baggage. The only rule is that when you’re going through the screening point, they must be empty if they are packed in your hand luggage. If your bottles are partially filled, they will not be allowed through airport security, even if the liquid content is below 3.4 oz / 100 ml. There aren’t any restrictions on thermos in checked baggage.
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