Hydro Flask Flex Straw Cap (Standard Mouth)
A straw lid that turns your Hydro Flask into a plane-seat bottle
A leakproof flip-up straw cap for Standard Mouth Hydro Flask bottles, with two cut-to-fit straws and a trim ruler. Dishwasher safe; for cold drinks only.
Our take
You don't need a new bottle to fix the annoying part of your old one. If you own a standard-mouth Hydro Flask, unscrewing the cap in a cramped plane seat is the problem, and this cap is the fix. The straw flips up with one hand and it's leakproof when closed.
Two cut-to-fit straws and a trim ruler come with it, and the parts come apart for the dishwasher. Check your bottle first, because it only fits Standard Mouth Hydro Flasks. It's for cold drinks only, never hot coffee or anything carbonated. A straw also means more parts to keep clean.
If your bottle matches, this is the upgrade we'd make. Check the price and your mouth size before you order.
Who it’s for
Hydro Flask owners who want one-handed sipping on flights, buses and long drives.
Skip it if
Skip it if you mostly carry hot drinks or don't own a standard-mouth Hydro Flask. The plain cap that came with your bottle is fine.
Hydro Flask Flex Straw Cap (Standard Mouth): questions people ask
Will this straw lid fit a wide-mouth Hydro Flask?
No. It's made for Standard Mouth Hydro Flask bottles only, so check which mouth size you have.
Can you use a straw lid with hot drinks?
Not this one. Hydro Flask says it's for cold drinks only, not hot or carbonated ones.
Do straw lids leak in a bag?
It's leakproof with the straw closed. Pressure changes on a flight can still push a little out, so close it before takeoff.
Where we recommend it
More in Water Bottles & Hydration
Hydro Flask 24 oz Wide Mouth Bottle with Flex Straw Cap
The right size for road trips and city days, but the straw lid is more work to clean in a hotel sink than a screw cap.
Nalgene 32 oz Wide Mouth Bottle
A tough, light quart for hikes and road trips that pairs with many water filters, but it isn't insulated and the wide mouth splashes on the move.
Hydro Flask 18 oz Standard Mouth Bottle with Flex Cap
Small enough for a side pocket on city days, but you'll refill a lot in the heat, so hikers should go bigger.
Prices change often — the price on the retailer’s page is the one you pay.