Best insulated food flasks in the UK
An insulated food flask keeps soup or stew above 60°C for roughly six hours if you pre-heat it: fill with boiling water, leave five minutes, empty, then add piping-hot food. Wide-mouth stainless steel models are easiest to fill, eat from and clean.
What matters when you're choosing
- Capacity of 470-500ml suits one adult lunch; 700ml if it is a main meal.
- Check the lid is dishwasher-safe — the seal is where flasks fail first.
- Double-wall vacuum stainless beats plastic-lined flasks on both heat retention and lifespan.
Our picks, scored independently
Black+Blum
Black+Blum Stainless Steel Bento Box
The Black+Blum Stainless Steel Bento is a premium, plastic-free lunch solution featuring a vacuum-sealed lid and a fork, ideal for eco-conscious UK commuters.
The Bambu Reusable Bamboo Sporks are a durable, plastic-free alternative to disposable cutlery, handcrafted from organic bamboo for eco-conscious UK diners and campers.
Klean Kanteen
Klean Kanteen TKWide 473ml Insulated Flask
The Klean Kanteen TKWide 473ml Insulated Flask is an exceptional, B Corp certified reusable bottle that keeps drinks hot for 14 hours and cold for 47 hours with 18/8 steel.
The Wearth London Glass and Bamboo Food Storage Container set is a premium, plastic-free kitchen essential offering leak-proof, sustainable food prep for UK households.
Ocean Bottle
Ocean Bottle 500ml Reusable Water Bottle
The Ocean Bottle 500ml Reusable Water Bottle is a premium, ethically made flask that funds the collection of 1,000 ocean-bound plastic bottles for every single unit sold.
Elephant Box
Bento Large Stainless Steel Lunch Box
The Elephant Box Stainless Steel Lunch Box is a heavy-duty, 2-litre plastic-free container built to last a lifetime, ensuring toxin-free and sustainable meal prep for UK workers.
The Stasher Reusable Silicone Storage Bag is a plastic-free kitchen essential that replaces single-use bags with durable, food-grade silicone for cooking and storage.
Bee's Wrap Vegan Reusable Food Wraps offer a sustainable, plant-based alternative to plastic film using organic cotton and candelilla wax to keep your kitchen storage eco-friendly.
The Black+Blum Glass Lunch Pot is a premium 600ml leak-proof container featuring a protective wood fibre base, ideal for stylish and sustainable British meal prep.
The Chilly's Series 2 Water Bottle is a premium insulated flask that offers 24-hour cold retention and an antimicrobial drinking surface, making it an ideal eco-friendly UK choice.
Huski Home
Huski Home Recycled Rice Husk Lunch Box
The Huski Home Recycled Rice Husk Lunch Box is highly recommended for eco-conscious UK diners, offering a durable, BPA-free, and biodegradable alternative to plastic food storage.
The Stasher Reusable Silicone Storage Bag is a high-quality, plastic-free alternative for UK kitchens, offering an airtight Pinch-Loc seal and exceptional durability for eco-conscious food storage.
Common questions
How long does a food flask keep food hot?
Five to eight hours above safe serving temperature when pre-heated and filled to the top. A half-full flask cools much faster.
Can you put a food flask in the dishwasher?
Most stainless bodies are hand-wash only; lids are usually dishwasher-safe. Dishwasher heat can degrade the vacuum seal over time.