LoTech Sales Blog | Branded Product Tips & Guides

Are Drink Tumblers Leak-Proof?

Written by Brandon Anderson | Jan 10, 2024, 3:00:00 PM

You toss your tumbler in a bag, and an hour later your laptop sleeve is soaked in iced coffee. Sound familiar? Here's the truth about tumblers and leaks.

The short answer

Most tumblers are spill-resistant, not leak-proof. A good lid keeps drinks in when the tumbler is upright or gets bumped, but sip openings and straw holes will leak if it tips over or rides sideways in a bag. For true leak-proof carry, you need a lid with a gasket and a fully sealing closure, or a screw-top bottle.

Leak-proof vs. spill-resistant

Term What it means Good for
Leak-proof A sealed lid with a gasket and a closed opening. No leaks even upside down. Bags, backpacks and car rides
Spill-resistant The lid limits splashes, but it can drip or leak if tipped Desks, cupholders and walking around
Open or straw lid Leaks if it tips over Sitting on a table

Where tumblers leak

  • The sip opening, especially if the slider doesn't fully close
  • The straw hole, which is open by design
  • The gasket, if it's missing, twisted or not seated after washing
  • The lid fit, if it's a press-on lid that isn't pushed all the way down
  • A cracked lid, which is easy to miss

How to tell if your tumbler is leak-proof

  • Check the product description. Look for the words leak-proof, not spill-proof or splash-resistant.
  • Look for a gasket in the lid and a closure that fully seals the opening.
  • Test it at home: fill it with water, close it, turn it upside down over the sink and give it a gentle shake.

If it isn't labeled leak-proof, don't trust it in your bag.

Leak prevention tips

☐ Re-seat the gasket every time you wash the lid
☐ Don't fill it all the way to the rim
☐ Close the slider before you walk
☐ Carry it upright
☐ Be careful with hot and fizzy drinks, since pressure can push liquid out of the lid

A good lid does double duty, too. The same seal that stops leaks helps hold temperature. Here's how tumbler lids affect insulation.

Shop the 20 oz tumbler →

Need something that can ride in a bag? A bottle with a screw-on cap is the safer bet. Here's how a thermos compares to a tumbler.

Quick answers

Can I put my tumbler in my bag?
Only if it's labeled leak-proof and the lid is fully closed. Otherwise, carry it upright.

Why does my tumbler leak from the lid?
Usually a gasket that isn't seated, a lid that isn't pushed on all the way, or an open sip or straw hole.

Do tumblers leak if they tip over?
Most do, a little, unless they have a fully sealing lid.

Drinkware your team will actually carry

Want tumblers engraved with your logo?

Tell us the colors, the quantity and your logo. Our 20 oz and 30 oz tumblers include a 3″ laser engraving.

Talk with a brand ambassador Shop drinkware