After sharing 27 easy bento box ideas for kids, I received many questions like this, “How do you pack hot and cold food?” Let’s talk about how to keep lunch warm or cold in the lunchbox. I’ll share the fail-proof methods that I use for packing a warm meal and cold lunches that stay fresh for hours. Plus, 22 hot lunch ideas and 16 cold lunch ideas!

3 lunchboxes on the ground: with chicken nuggets, with soup, and with pancakes.
Whether you need to pack a hot or cold lunch, these tips will keep your kids lunch safe and enjoyable for hours!

How to Keep Lunch Warm

Hot food is my favorite food to pack for kids’ lunches. Most of these foods are leftovers from a previous dinner or breakfast. When I pack these foods in the early morning, I want them to still be warm at lunchtime.

  • First, consider if the food being packed actually needs to be warm or hot when served. Roasted vegetables, quesadillas, grilled cheese, pizza, fried rice, and meatballs are usually served in a warm/hot state, but they may also be served at room temperature (use an ice pack for safety).
  • There are some foods that just taste best when served warm/hot. If you plan to serve these foods (hot soup and certain leftovers like stir-fry), you’ll need to purchase a good thermos. Using a thermos is the BEST way to keep food warm until lunchtime.

  • LUNCHBOTS 8-OUNCE THERMOS – This thermos holds up to 8 ounces of food; the perfect size for preschool-elementary school children. It will keep food warm for up to 6 hours or cold for up to 12 hours (great for yogurt, chocolate overnight oats, or a cold Italian pasta salad). Cost: $25
  • LUNCHBOTS 16-OUNCE THERMOS – For a middle schooler and up (including adults), use a large thermos. 16 ounces is the perfect size for a larger appetite. The LunchBots thermos will keep food warm for up to 6 hours or cold for up to 16 hours. Cost: $30
  • 16-OUNCE THERMOS WITH SPOON – If you want a thermos with a built-in spoon that folds up into the thermos, this 16-ounce thermos from DaCool is my favorite. The lid of the thermos may also be used as a small bowl (pictured below). Cost: $22
  • OMIELIFE BENTO BOX WITH BUILT-IN THERMOS – A plastic bento box for young children (preschool-3rd grade) with a built-in, removal thermos that’s easy to open. My kids loved this box when they were little and it was a great way to pack hot lunches without purchasing a separate thermos. This lunchbox is leak-proof and the thermos holds up to 8.5 ounces of food. Cost: $45
Thermos lunch with oatmeal, grapefruit on the side, with cucumbers and chips.
Hot oatmeal in the thermos with a grapefruit, string cheese, cucumber slices, and chips in the LunchBots Bento Box.

HOW TO CHOOSE A GOOD THERMOS:

  • Choose an insulted thermos. This should be clearly labeled in the description of the product (on the tag, website, etc.). All of the recommendations above are insulated.
  • Check the number of hours the company says food will stay warm or cold in the thermos. This number should match your need. For example: If you pack a hot lunch at 7am and your child eats lunch at 12noon, make sure food will stay hot for 5 hours.
  • Make sure your child can easily open the thermos. Small hands may have a difficult time with a large thermos lid. Test this out with your child. And practice how-to open and close the thermos before sending a thermos in the lunchbox.
Hot thermos lunch with chicken noodle soup, bread, apple slices, and energy bites.
Instant Pot chicken noodle soup, apple slices, sourdough bread and butter, and an energy bite in the Omielife box.

How to Keep Food Warm in a Thermos

HOW TO USE A THERMOS STEP BY STEP

  1. Remove the lid from the thermos and fill the thermos with hot water.
  2. Let the hot water sit in the thermos, with the lid on, for about 5 minutes. During this time, use the oven, stove-top, or microwave to warm up the food.
  3. Dump the hot water. Fill up the thermos with hot food.
  4. Secure the lid on the thermos.
  5. Place the thermos in an insulated bag.
Pouring hot water from a kettle into a thermos.
Add hot water to the thermos. Pictured here: Omielife Bento Box with Built-in Thermos.

Step 1: Fill Thermos with Hot Water

Remove the lid from the thermos. Fill the thermos with boiling water. Warm water from the sink also works.

Holding a thermos in two hands, after adding hot water.
Let the hot water rest in the thermos, with the lid on, for 5 minutes. Now is a great time to warm up food.

Step 2: Rest for 5 Minutes

Let the hot water sit in the thermos, with the lid on, for about 5 minutes. During this time, use the oven, stove-top, or microwave to warm up the food.

Step 3: Dump Water & Fill Thermos with Food

Dump the hot water. Fill up the warm thermos with the hot food. If you’re filling the thermos with dry food (i.e. grilled cheese sticks, mini burgers), wipe out the bottom of the thermos and around the sides so any leftover water doesn’t get the food soggy. 

Placing the lid on the thermos.
Place the lid tightly on the thermos. It’s important that the lid is secured quickly after adding the food.

Step 4: Secure the lid on the thermos.

Step 5: Use an Insulted Bag

Place the thermos in an insulated bag. Do not use a brown paper bag. When packing a thermos in a lunch bag, avoid placing an ice pack directly on the thermos. The ice pack can interfere with keeping the food warm.

How to Pack Hot and Cold Foods in The Same Lunch

There are a few ways to do this…

  • Pack Non-Perishable Foods: Avoid perishable foods that require an ice pack and focus on foods that may be served at room temperature: crackers, a sandwich that doesn’t require an ice pack (like peanut butter and jam), fresh fruit or vegetables, etc. 
  • Separate Hot and Cold Foods: Separate the cold food and ice pack from the thermos. Use a small wash cloth to wrap the thermos, a divided box like the Omielife box, or a small piece of cardboard separating the thermos from the cold food.
  • Use a Lunch Bag With Two Compartments: Use an insulated lunch bag with two compartments that separate a thermos from the cold food sources. I love the LunchBots two-compartment lunch bag. I pack the thermos on top and the LunchBots Bento Box with an ice pack in the lower half. Bentgo makes a similar lunch bag.
Macaroni and cheese in a thermos with rolled up ham, cantaloupe, and broccoli on the side.
Separate the hot food in the thermos from cold food, using dividers like the Omielife box (pictured here), a piece of cardboard, or wrap a small towel around the thermos.

PRO TIP – PACK REUSABLE UTENSILS: You’ll need a spoon for hot meals like soup, oatmeal, or fried rice. And a fork for anything like macaroni and cheese or spaghetti. I love this pack of reusable utensils.

What to Pack for Hot Lunch

Leftovers from dinner or breakfast make the best and easiest hot lunch as you can easily warm them up the following morning!

And if you have picky eaters, leftovers are a great way to pack a food your child is familiar with and will eat during lunchtime.

Looking for warm food ideas to pack in the thermos? Check out 8 hot lunch ideas for school with pictures of every lunch!

Here are a few of my favorite leftovers to pack for a hot lunch. Each idea is a main that I pair with a fruit, veggie, and crunch (my simple school lunch framework).

22 Hot Lunch Ideas

FREE PRINTABLE

42 EASY SCHOOL LUNCH IDEAS CHEAT SHEET

Nourishing meal ideas for effortless school lunches. Download your free lunch guide.

PRO TIP – HOW TO KEEP FOOD WARM WHEN IT DOESN’T FIT IN A THERMOS: If you want to pack hot lunches that don’t fit in a thermos, like taquitos, grilled cheese, burgers, pizza, bean burritos, or quesadillas, warm the food in the microwave, stove-top, or oven, then wrap the food in aluminum foil. This will keep a warm lunch for a couple of hours. Many of these foods, I serve at room temperature, packed with an ice pack. But if your child prefers a warmer temperature, foil is the best option.

Pizza in the lunchbox with apricots, roasted broccoli, and a beef jerky stick.
If you want to keep pizza, quesadillas, and other foods warm, wrap them in foil after reheating, then place in the lunchbox.

How to Pack Cold Food in the Lunchbox

“Cold food” is anything that is delicate in nature, meaning it needs to be kept in a chilled state in order to taste best and maintain a safe temperature (we don’t want a foodborne illness). This may include yogurt, cheese, chicken or tuna salad, deli meat sandwiches or wraps, eggs, and mayo-based foods. 


  • INVESTIGATE BEFORE YOU BUY – Ice packs can vary in how long they will keep food chilled, so it’s important to read up on the ice pack you plan to purchase. If you purchase the ice pack from Amazon, read the reviews and see what customers have to say about performance. Here’s the ice packs my kids use.
  • USE AN INSULATED LUNCH BAG – The lunch bag can be a factor in how well cold items remain cold. A cheap lunchbox (meaning, cheaply made and poorly insulated, or not insulated) may allow too much of the cold (from the ice pack) to escape. I love the LunchBots bag. It has two compartments, one where I can pack an ice pack with the LunchBots Bento Box. And another compartment up top where I can pack a thermos or school snacks.
  • AVOID PLASTIC AND BROWN BAGS – An insulted bag is essential when packing a cold lunch and an ice pack. Avoid sending an ice pack in a brown bag or plastic bag.
  • PACK TWO ICE PACKS – If you’re particularly concerned about keeping a food chilled (something like tuna salad or deli meat), you may want to pack two ice packs in the lunch bag, one on top of the lunchbox and one on the bottom. 
  • COLD DRINKS – To keep drinks, like ice water or a smoothie, cold until lunch, use an insulted thermos like a Hydroflask. Most insulated water bottles work for both hot drinks and cold drinks.
Placing two ice packs in a lunchbag with a stainless steel lunchbox.
The best way to pack a cold lunch is to add an ice pack, or two, to an insulated lunch bag.

Now, let’s talk about some cold lunch ideas. Each of the ideas below are main lunch ideas, which I then pair with a fruit, veggie, and crunch (my simple school lunch framework). If you want to see what each lunch looks like (a photo), check out this post: 27 Easy Bento Box Lunch Ideas for Kids and School.

16 Cold Lunch Ideas For School

  • Homemade Lunchable: Deli Meat, Crackers, and Cheese
  • Homemade Pizza Lunchable: Mini pizza crusts, mozzarella cheese, and sauce.
  • Pizza: There’s no need to warm up pizza, serve it cold with an ice pack.
  • Egg Muffins: Baked eggs in a muffin tin are a great breakfast and lunch to prep ahead and pack cold in the lunchbox with an ice pack.
  • Turkey Roll-Ups: Rolled up turkey or ham with a slice of cheese (add spinach if your child likes leafy greens).
  • Classic Sandwich: Deli meat or shredded chicken and cheese and lettuce.
  • Peanut Butter and Jam Sandwich
  • Pancake or Waffle Sandwich: Add cream cheese, jam, or nut butter to make a sandwich with two pancakes or waffles.
  • Hard-Boiled Eggs
  • Ground Beef Taquitos: Yes, this lunch can be served hot in a thermos, but it’s great to pack with an ice pack and eat at room temperature.
  • Yogurt Parfait: Spoon plain yogurt into a leak-proof container, add honey and fruit. Then place granola on the side to sprinkle over top at lunchtime.
  • Banana Sushi Roll Ups: Smear peanut butter or sunflower seed butter on a tortilla, add a banana, then roll up and slice.
  • Pancakes: Eaten at room temperature, with an ice pack in the lunch bag. Add a small leak-proof container of maple syrup and a protein, like rolled up turkey.
  • Hummus and Turkey Pita Sandwich: Spread hummus in a pita, add sliced turkey, and cucumber.
  • Salad with Homemade Ranch or Vinaigrette Dressing
  • Banana Bread Cream Cheese Sandwich: Spread cream cheese between two slices of banana bread. (I love this almond flour banana bread or turn these einkorn banana muffins into bread.)
  • SEE 27 EASY LUNCH IDEAS HERE
Yogurt lunch with fruit, carrots, rolled up ham, and a breakfast cookie.
An easy cold lunch: yogurt parfait (yogurt and fruit), carrot sticks, breakfast cookie, and rolled up ham.
FREE PRINTABLE

42 EASY SCHOOL LUNCH IDEAS CHEAT SHEET

Nourishing meal ideas for effortless school lunches. Download your free lunch guide.

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