Nothing ruins the first hour of a trip like opening your bag to a shampoo spill that turns your sweater into a wet rag. The fix usually isn’t buying “smaller” products, it’s choosing carry on toiletries with packaging that can handle pressure changes, jostling, and rough zippers.

This guide covers what TSA still allows in December 2025, what “won’t leak” really means (cap design matters more than marketing), and smart formats to pack so your quart bag stays clean. More money saved on replacement products also means more room in the budget for fun, including travel deals you’ll actually use.

TSA liquid rules in 2025 (the part you can’t ignore)

For U.S. flights, TSA’s liquids rule is still the 3-1-1 standard: each liquid, gel, or aerosol must be 3.4 oz (100 ml) or smaller, and everything must fit into one clear quart-size bag per passenger. TSA’s official guidance is here: Liquids, Aerosols, and Gels Rule.

A few quick clarifiers that trip people up:

• Toothpaste counts as a gel.
• Sunscreen counts as a cream or lotion (still a liquid rule item).
• Hair spray and dry shampoo are often aerosols, and size matters.
• Most solids (bar soap, shampoo bars, deodorant sticks) don’t need to go in the quart bag, but screening officers can always ask to inspect anything.

If you’re also trying to avoid bag fees, it helps to know your airline’s exact carry-on limits. This carry-on luggage dimensions by airline guide makes it easier to pack confidently.

What “won’t leak” really means (look for these features)

Leak-proof isn’t a vibe, it’s physics plus good packaging. When cabin pressure changes, containers can burp product out through weak seals. Use these criteria when shopping for carry on toiletries:

Choose the right closure

• Screw caps with an inner gasket: best for liquids and thin gels.
• Flip-top caps: convenient, but only reliable if there’s a tight snap and a clean seal.
• Disc-top caps: decent for thicker lotions, riskier for watery products.

Prefer containers that resist pressure

• Airless pump bottles: great for creams and serums, less air means less expansion.
• Locking pumps (twist-to-lock or clip lock): helpful, but still bag them.
• Tubes with a strong crimp: better than cheap tubes that wrinkle and split.

Avoid weak points

• Wide-mouth jars can ooze around the lid if they’re overfilled.
• Some spray tops leak from the stem or collar, even when capped.

Travel pods that work

• Silicone squeeze bottles can be solid if the cap is sturdy and the opening isn’t too wide.
• Contact-lens style pots are best for thick creams, not runny liquids.

Best carry-on-friendly toiletries by format (with TSA-friendly sizes)

Instead of chasing “the best brand,” pick formats that behave well in a bag. Here are the options that tend to stay put.

Solids (least messy, easiest through security)

Solids are the closest thing to spill-proof. They also free up space in your quart bag.

• Shampoo bar (solid): look for a hard, cured bar, not a soft melt-prone one. Pack in a vented tin or a small dry bag.
• Conditioner bar (solid): slightly softer than shampoo bars, keep it in its own case.
• Bar soap or syndet bar (solid): simple, cheap, and reliable.
• Deodorant stick (solid): doesn’t count toward liquid limits, and it won’t pop open mid-flight like some gel deodorants.

Creams and thick lotions (low leak risk when capped well)

Thicker products travel better than watery ones, as long as you don’t overfill.

• Moisturizer (cream): pick a travel-size tube or an airless pump. If you decant, use a small jar only for thick formulas.
• Face cleanser (gel or cream): a travel-size tube is safer than a flip-top bottle. A cleansing balm (solid-to-oil) also packs nicely.
• Sunscreen (cream or lotion): choose a 3.4 oz (100 ml) tube. Thin sunscreens leak more often than thick ones, so packaging matters.

Liquids (doable, but choose the container like you mean it)

Liquids are the usual offenders. If you’re bringing them, bring fewer and pack them smarter.

• Shampoo (liquid) and body wash (liquid): use screw-cap bottles with a gasket, or silicone bottles with a tight cap. Avoid flimsy flip tops.
• Micellar water (liquid): only worth it if you have sensitive skin. Use a small, well-sealed bottle and keep it in the quart bag.
• Fragrance (liquid): a small spray vial is fine, but it’s still a liquid. Cap it, bag it, and keep it away from electronics.

For product roundups and container ideas, these references can help you compare styles and materials: Condé Nast Traveler’s reusable mini toiletries overview and Travel + Leisure’s tested toiletry bottle sets.

Aerosols (the riskiest, and easiest to get wrong)

Aerosols are allowed under the same 3-1-1 limits, but they’re more likely to leak and more likely to be oversized.

• Hairspray (aerosol): only pack if you truly need it, and keep it small.
• Dry shampoo (aerosol): convenient, but often ends up too big. A non-aerosol powder version can be easier.
• Shaving cream (aerosol): many cans are oversized. A shave bar (solid) or shave gel in a small tube is simpler.

A TSA-compliant quart-bag packing example (ready to copy)

Here’s a realistic setup that fits the rules and keeps leaks contained:

• Shampoo, liquid, 2.0 oz bottle
• Conditioner, cream, 2.0 oz tube
• Toothpaste, gel, 1.0 to 1.4 oz tube
• Face wash, gel, 1.0 to 2.0 oz tube
• Moisturizer, cream, 1.0 oz airless pump
• Sunscreen, lotion, 3.4 oz tube
• Contact solution, liquid, 3.0 oz bottle (if needed)

Everything above goes in one quart bag. Your solids (bar soap, shampoo bar, deodorant stick) can ride outside it.

Packing tips that stop leaks before they start

A few habits do more than any fancy bottle.

Don’t fill containers to the top: leave a little air space so expansion doesn’t force product out.

Equalize pressure: after landing, crack the cap open slightly in the bathroom (not over clothes), then re-seal.

Add a secondary seal: place a small piece of plastic wrap over the opening, then screw the cap on. It’s simple and it works.

Use a real zip bag: even “leak-proof” containers can fail. A thicker zip bag or two is cheap insurance.

Store upright when possible: quart bag near the top of the carry-on, not crushed under shoes.

What to skip (even if it’s your favorite)

Some toiletries are just asking for trouble in a carry-on:

• Messy pumps without a lock, especially thin lotions and soaps
• Glass bottles, including skincare in heavy jars
• Oversized aerosols that get confiscated, even if they’re half empty
• Watery toners in flip-top bottles, they seep through tiny gaps

A minimalist capsule toiletry kit for 2 to 4 days

If you want to pack light, this kit covers most trips and keeps the quart bag calm:

• Shampoo bar, solid
• Bar soap or body wash sheet strips, solid
• Deodorant stick, solid
• Toothpaste, gel, travel tube
• Moisturizer, cream, 1 oz tube or airless pump
• Sunscreen, lotion, 3.4 oz tube
• One multipurpose balm, solid (cuticles, dry spots, flyaway hair)

That’s it. Add makeup or shaving items only if you’ll use them daily.

Conclusion

Leak-free packing comes down to choosing stable formats, trusting good seals, and treating your quart bag like a tiny toolbox, not a junk drawer. With the right carry on toiletries, you’ll spend less time cleaning up spills and more time enjoying the trip.

Always double-check TSA guidance and your destination and airline rules before you fly, especially for aerosols and international connections. Pack smart, and your bag won’t surprise you at the hotel.