Bento box UK buying guide: monbento, Yumbox, Sistema and more compared

What is a bento box?

A bento box is a packed lunch with compartments, so each food has its own space. The idea comes from Japan. In the UK, the word covers anything from a two-tier box for an office lunch to a six-section tray for a school bag.

The reasons to buy one are practical. Wet and dry foods stay apart, portions are visible, and the box packs flat in a bag. It suits anyone who dislikes soggy bread or sauces touching, whether that is a preference or something stronger.

What makes a good bento box?

Seals, size and washing decide it. Check these before colour.

• How the seal works. A tray with a lid pressed onto it is the simplest. The Yumbox uses a silicone-lined lid over six sections. The monbento stacks two containers with sealed inner lids and a valve.
• Capacity. Count in millilitres, not compartments. The monbento holds 1 litre across two 500ml tiers, which is a full adult lunch. Yumbox's main sections hold about half a cup each, which suits a child, and an adult may need more.
• Materials. monbento lists PBT for the lid and containers and says the box is BPA-free. Check the materials list on anything you buy.
• Dishwasher rules. Top rack and a gentle cycle for the monbento. The Yumbox lid wants hand-washing to keep the seal.
• Microwave rules. monbento says up to 3 minutes at 500W with the silicone valve open. Check each product, because they differ.
• Warranty. monbento's price-list page says 3 years and a banner says lifetime, so it is inconsistent. The MB Original care page describes a lifetime warranty for manufacturing and finish defects, not impact damage, misuse or normal wear.

Which bento box suits an adult?

The monbento MB Original is the one to look at. Its dimensions are 18.5 by 9.4 by 10cm, it weighs 480g, and two 500ml tiers give you a main and a side without mixing them. monbento's single boxes ran from £29.90 to £41.90 on its UK page, with several colours at £30.50 and graphic designs at £37.90.

It comes without cutlery. Some bundles appear to include it, and monbento's page does not say what is in each.

Which suits children?

The Yumbox Original is built around small portions. Six sections let a child have a little of several things, and the lid keeps yoghurt away from crackers. Yumbox says its latch is made for small hands. Try it at home first, because a lunch box that a child cannot open is a bad school day.

What if you want to spend less?

Four Sistema KLIP IT Plus 1 litre tubs. Use one food per tub and the effect is the same as a bento, if bulkier. The clips are on the lid, so one tub stays shut until you open it. Retailer pages say the tubs are BPA-free and top-rack dishwasher safe, but disagree on microwave use, so read the label on yours.

What about hot food?

A bento box is a poor fit for a hot meal unless your workplace has a microwave. The Joseph Joseph GoEat pot is built for soup or stew in the lower pot with bread or a topping on top. The Thermos Stainless King keeps hot food hot by insulation. The listing says 9 hours hot and 14 hours cold. It holds 470ml in one compartment, so foods will touch.

How do you look after a bento box?

Rinse it soon after use. Food left to dry on a silicone seal is harder to shift, and a seal that is not clean may not close as well.

Follow each maker's washing rules rather than assuming. Top-rack dishwasher on a gentle cycle for the monbento. Hand-wash the lid on the Yumbox. Open the monbento's silicone valve before microwaving so steam can leave. Seals are the part that wears out first, so check them if a box starts to leak. monbento's page says its warranty does not cover normal wear.

Pack with the seal in mind too. For the monbento, close every part fully: the page says the upper lid does not add to airtightness. Carry any lidded tray flat, with the wettest food at the bottom of its section.

Things to know

• Keep it cool. The Food Standards Agency says not to leave food out for longer than two hours when temperatures are higher than usual, and recommends frozen ice packs and cool bags. That is picnic advice, and it applies sensibly to a lunchbox.
• Prices move. Prices here come from our product data. monbento's UK page showed a range of £29.90 to £41.90 depending on colour.
• Warranty wording. monbento's own pages disagree between 3 years and lifetime. Ask before you rely on either.
• We have not tested any of these. Details come from the makers' pages and listings, read on 2 November 2026. We could not load the Yumbox or Joseph Joseph pages on that date, and those details come from our earlier check on 11 September.