Can I Bring A Thermos On A Plane?

Your Complete Guide To Bringing A Thermos Or Personal Water Bottle Your Next Flight


If you’re one of those lovely people who dislike single-use plastic water bottles and prefer using a thermos or reusable water bottle, this article which discusses the rules for bringing personal water bottles in your carry-on luggage through airport security checks will provide you with the TSA’s rules on the topic.

Fortunately, the short answer is that you are allowed to bring your favorite thermos bottle on domestic and international flights, but there are some rules you need to be aware of before packing your yeti cup or hydro flask in your hand luggage.

The Problem With Plastic Water Bottles

Before we discuss the alternatives to single-use plastic water bottles and how to bring them with you on your flight, here are some facts about why it is a good idea to avoid them in the first place.

  • Every second, many 1000s of people open plastic water bottles around the world.
  • Every day many 100s of millions of water bottles are thrown away, most of which end up in landfills or as pollutants in rivers and oceans.
  • Less than 10% of water bottles globally are recycled.
  • Fewer than 50% of the water bottles and plastic that goes into recycling bins in homes are actually recycled.
  • The United States represents less than 5% of the world’s population but produces 30% of the world’s plastic trash.
  • In the USA, it takes 40,000 18-wheeler trucks to deliver all the country’s bottled water.
  • Americans drink more bottled water than beer and milk every year and the rate of consumption grows by 10% a year.
  • Plastic makes up 90% of all the plastic floating in the world’s oceans. There are nearly 40,000 pieces of trash per square mile in our oceans.

While these statistics can be overwhelming, and it is understandable to feel helpless, there are things you can do as an individual that can have a real impact on our planet.

The good news is that, like you, many people from all over the world are becoming conscious of the problem of plastic and are determined to be part of the solution.

Many have chosen to take the “no plastic bottles pledge”.

While this is an admirable commitment, it takes dedication to completely divorce yourself from plastic water bottles.

Reuseable Personal Water Bottles

The good news is that every type of personal thermos is allowed in your carry-on and checked luggage.

However, there is one major restriction for air travel with metal water bottles and thermos’.

According to TSA regulations, the only requirement is that they must be completely empty to successfully bring them through an airport security screening.

As a general rule, you will face no problems bringing an empty water bottle and thermos through the x-ray machines at the airport security checkpoints. Security personnel and TSA agents will not confiscate any type of empty water bottle from a stainless steel travel tumbler to a coffee thermos or travel mug from your carry-on bags.

Pro Tips

Because you are not able to bring your full water bottle or thermos through a TSA checkpoint in your carry-on baggage, you might want to save the room in your hand baggage for other items.

However, if you are planning to bring your own coffee mug on the plan to use instead of the paper or plastic options an airline flight attendant will offer you for your hot coffee, then by all means bring your own mug – you will not have a run-in with a security officer if you choose to do so.

When you DO bring empty stainless steel water bottles, an empty thermos, or a personal empty bottle with you on your flight you will usually be able to refill it at a water fountain at your arrival airport.

Special Instructions & TSA Rules

The reason you are not allowed to bring a full stainless steel bottle through an airport security checkpoint is because of the TSA (transportation security administration) 3-1-1 Rule.

The TSA’s 3-1-1 rule is specific to what you are allowed to pack in your carry-on luggage.

While most solid food items (except for spreadable foods like peanut butter or other types of similar canned food) are allowed in your carry-on, liquid items which are in containers larger than 3.4 oz (100 milliliters) are not allowed in your carry-on bags.

To understand TSA security rules fully, visit the TSA website.

Also, watch their YouTube video above to learn the most common items that are and are not allowed on domestic flights as well as international fights.


The next time you book a long flight, you will have no trouble getting your empty thermos or personal water bottle through any airport security metal detector on your way to your final destination.

The only way to legally bring a thermos or reusable stainless steel water bottle onto a plane is if it is completely empty.

You will not encounter any need for additional screening or security checks if you are sure to follow all TSA guidelines for liquids.

According to the TSA’s “3-1-1 liquids rule”, you are not allowed to bring liquids onto your flight in sizes larger than 3.4 oz (100 milliliters).

This includes all types of liquids.

Whether it’s liquid baby formula or breast milk, alcoholic beverages, coffee, or water you must abide by the 3-1-1 rule.

Solid foods like potato chips, sandwiches, and candy are all allowed on planes.

Spreadable foods like peanut butter, cottage cheese, honey, or Nutella chocolate spread are only allowed in your checked bags if they are in larger sizes than 3.4 oz (100 milliliters) – try to get anything larger past an airport security checkpoint in your carry-on baggage and they will certainly be confiscated.

If you want to bring liquids on a plane make sure they are not in your thermos or personal water bottle.

Instead, pack them in a clear plastic leak-proof container such as a zip-loc bag.

Everything you can fit into quart-size clear plastic bags are the maximum number of liquids you are allowed to bring with you on a plane.

Any additional liquid items will need to go in your checked bag.

If you are one of the environmentally-conscious individuals who is committed to getting away from using single-use plastic water bottles, and you are devoted to carrying your own thermos or water bottle with you on your next flight, bravo to you.

Just make sure that your water bottle or thermos is empty and you will be in great shape.

Dreaming of Moving to Italy?🇮🇹 - Get this FREE podcast & be INSPIRED by someone who moved from New York to Italy in 2020!

*By signing up for this Podcast you’ll also be joining our mailing list through which we will keep you up to date on all things Italian!  We never sell your information and you can easily unsubscribe at any time.

Share This Post


Author Info:

Picture of Nathan Heinrich

Nathan Heinrich

Nathan is a writer, designer & horticulturist. He is the founder and Editor-in-Chief of "All Roads Lead to Italy" Magazine & host of the Top-10 Travel Podcast, "I'm Moving To Italy!". Nathan was born and raised in a 6th generation farming family in Northern California, he is currently, a dual Italian citizen, living in the Prosecco Valley of Northern Italy, near Venice.

Continue Reading