How to Pack Toiletries So They Don't Leak: 7 Fixes That Actually Work

To pack toiletries so they don't leak, squeeze the air out of every bottle before you close it, seal the neck with cling film under the cap, fill bottles no more than about three quarters full, and pack them upright inside a second zip bag. Those habits stop most spills. The fix that stops all of them: pack fewer liquids, because a solid shampoo or body wash bar has nothing to leak.

Below: why bottles leak on planes, the 7 fixes, and what to do if one leaks anyway. Still deciding what to pack? Start with our travel toiletries checklist.

• 1. Why do bottles leak on planes?
• 2. Fix 1: Squeeze the air out before closing
• 3. Fix 2: Put cling film or tape under the cap
• 4. Fix 3: Don't overfill
• 5. Fix 4: Use screw caps and lock the pumps
• 6. Fix 5: Bag within a bag
• 7. Fix 6: Pack them upright, in the right spot
• 8. Fix 7: Stop packing liquids you don't need
• 9. Which toiletries leak most?
• 10. What should you do if something leaks?
• 11. Summary
• 12. Frequently asked questions
• 13. Sources

Why do bottles leak on planes?

Bottles leak on planes because the cabin pressure drops after take-off, so the air trapped inside a bottle expands and pushes liquid out through the cap. According to a National Research Council report, airliner cabins are typically pressurised to the equivalent of an altitude of about 1,800 to 2,400 metres (6,000 to 8,000 ft). The same report notes that gas trapped in the body can expand by as much as 25% at that pressure, which is why your ears pop (National Academies).

The air pocket in your shampoo bottle does the same. It expands and pushes liquid out through a flip-top not fully shut, a pump, or a loose thread. The hold is pressurised too, so checked bags aren't safe either.

So every fix below does one of three things: removes the air, blocks the exit, or contains whatever gets out. The last one removes the bottle altogether.

Fix 1: Why should you squeeze the air out before closing?

Less air in the bottle means less gas to expand, so there's less force pushing liquid out. With a soft squeeze bottle, fill it, then squeeze gently until the liquid reaches the neck and screw the cap on while you're still squeezing. It will look slightly pinched. That's what you want. This only works with soft bottles, which is one reason silicone travel bottles are popular.

Fix 2: Does cling film under the cap really stop leaks?

Yes, a square of cling film stretched over the opening before you screw the cap on is one of the simplest, most effective tricks there is. It adds a second seal right where leaks start. On flip-tops, a strip of tape over the closed lid stops it popping open.

Fix 3: How full should a travel bottle be?

Fill bottles to roughly three quarters, then squeeze out the air. An overfilled bottle has no room to flex, so liquid is forced into the thread.

If you want a sense of how much you actually need, how much shampoo you need for a week away walks through it by trip length.

Fix 4: Which caps leak least, and how do you lock a pump?

Screw caps leak less than flip-tops, and pumps leak most of all unless they're locked. Many pumps lock by twisting the head down; if yours doesn't, tape it.

With screw caps, wipe the thread clean before closing: dried product stops the cap sealing.

Fix 5: Why double-bag your toiletries?

A second bag doesn't stop a leak, it stops a leak from reaching your clothes. Put liquids in a resealable bag, then put that inside your washbag or a second zip bag.

For hand luggage, assume 100 ml per container in one transparent bag of up to 1 litre, even though some airports with newer scanners allow more. Our guide on whether you can take soap on a plane has the detail.

Fix 6: Where in your bag should you pack toiletries?

Pack bottles upright, caps up, in a part of the bag that won't get crushed. A standing bottle keeps liquid away from the cap. In a backpack, that means near the top against a stiff side; in a wheeled case, at the handle end. Keep shoes and books away from the washbag, and avoid outer pockets that get squashed in overhead lockers.

Our guide to what to put in a toiletry bag has more on organising the bag.

Fix 7: Can you stop packing liquids altogether?

For shampoo, body wash and face wash, yes: a solid bar does the same job and can't leak, because there is no liquid and no cap. Solids also stay out of your liquids bag.

Our article on solid toiletries for carry-on travel goes item by item, and we compare the two honestly in travel-size bottles vs solid bars.

To be straight about it, some things should stay liquid: high-SPF sun cream has no proper solid equivalent, and neither do liquid medicines or contact lens solution.

A bar is wet after use, so pack it in a ventilated tin or mesh pouch, not a sealed plastic bag. Our guides on how to travel with a shampoo bar and how to store a soap bar cover packing it wet.

Rinsed bars are 3-in-1 syndet bars: shampoo, body wash and face wash in one. The first ingredient is Sodium Cocoyl Isethionate, with no saponified oils (here's what a syndet bar is).

Which toiletries leak most?

Thin liquids in pump or flip-top bottles leak most, thick creams in screw-top tubes leak least, and solids don't leak at all.

Item	Leak risk	Fix
Shampoo and conditioner in flip-top bottles	High	Squeeze out air, cling film, tape the lid, or switch to a bar
Shower gel and face wash	High	Squeeze out air and cling film, or switch to a bar
Serums, oils, liquid foundation, pump lotions	High	Screw cap or taped pump, cling film, double bag
Sun cream	Medium	Tape the cap, pack upright, separate bag
Toothpaste tube	Low to medium	Close firmly and keep it out of crush zones, or use tablets
Roll-on deodorant	Medium	Tape the lid, or switch to a stick
Solid bars and sticks	None	Let the bar dry before packing it in a ventilated tin

The more of your washbag that's solid, the less you need to wrap, tape and double bag.

What should you do if something leaks anyway?

Get the leaking bottle out, contain it, and deal with clothes before the product dries into them.

1. Isolate it. Put the bottle in its own bag and move clean things away.
2. Blot, don't rub. Soak up what you can with tissues. Rubbing spreads it.
3. Rinse with cold water. Shampoo and shower gel rinse out but foam, so it takes a few rounds. Oils and sun cream may need a drop of washing-up liquid.
4. Dry it. Roll the item in a towel and press, then hang it.
5. Check the rest of the bottle. If the cap is cracked, don't repack it.

On a long flight, keep a spare zip bag handy; our list of long-haul flight toiletries has other things worth keeping within reach.

Summary

Bottles leak on planes because cabin pressure drops and the air inside them expands. Squeeze out the air, add cling film, don't overfill, lock pumps, double bag and pack upright.

The simplest fix is to pack fewer liquids. Swap shampoo, body wash and face wash for a solid bar and keep bottles for what genuinely needs to be liquid.

Frequently asked questions

Sources

The facts in this article are based on the sources below, checked in September 2026.

1. The Airliner Cabin Environment and the Health of Passengers and Crew. National Research Council, National Academies Press, 2002.