I tested Coleman’s Pro Cooler Box in a heatwave and it kept our drinks cold for 4 days straight

Our hunt for the best cool box that doesn’t cost a fortune stops right here with the new Coleman Pro 45 QT, a robust and very thoughtfully designed 42.5-litre passive cooler that retains ice for up to four days.

As any savvy outdoors fan already knows, a good cooler box is an essential companion, whether it’s for a long weekend camping trip, a long day at the beach, a fishing session or a few days at Glastonbury.

Designed to keep food fresh and drinks ice-cold for days at a time, a passive cooler box like the Coleman Pro 45 QT we’re reviewing here offers a practical and portable solution for preserving perishables while away from the convenience of your humble fridge.

I shall now tell you why I think this exceptional cooler strikes the perfect balance between size, performance and price. Take it away.

Coleman Pro 45 QT Cooler Box review

Price and availability

The Coleman Pro 45 QT is widely available in the UK and retails at around £200, though there are some great deals to be had. For bricks-and-mortar convenience, I’d suggest Go Outdoors as a first port of call, where it retails for £200.

Otherwise, visit Amazon where you can buy this product in rare blue for £179.99 or, for the best current deal, Stoves Are Us, which is selling the Pro 45 QT for a magical £135.

In the USA, this model retails at around $199.99 and is available directly from Coleman, Amazon ($169.99) and Target ($199.99).

How best to use a passive cooler box

Using a passive cooler box is easy peasy, but with a few smart steps, you can get the most out of its cooling power and keep your food and drinks fresher for longer. Unlike electric coolers, passive models rely entirely on insulation and ice to maintain a low temperature, so preparation is key.

Start by pre-chilling the cooler before you pack it by placing a bag of ice inside for a few hours – or even overnight – to bring the internal temperature down. At the same time, make sure the contents going in – especially high perishables like milk, meat and fish – are already fridge cold. Unlike a compressor fridge that simply ramps up the power when food is added, a passive cooler performs best when it’s not having to fight to chill warm items.

According to premium brand Yeti, to effectively cool a cooler box you should use a 2:1 ice-to-contents ratio, meaning two-thirds of the cooler should be filled with ice. However, the amount of ice you need also depends on the longevity of the trip and/or the amount of foodstuffs you’re taking so, if you’re just going for a group picnic, you might reduce the ice content to a couple of one-kilo bags so you can fit in a lot more food and drink.

The best way to load a cooler is to layer the ice and contents, ensuring ice is placed on the bottom and also layered throughout to minimise air gaps. It’s also advisable to use a few frozen gel packs on top since they not only melt more slowly, but the cold air sinks to the bottom, keeping the entire box cool. Finally, pack the cooler as full as possible, since a packed cooler retains cold temperatures better than one with empty space. Given that air is the chief adversary of the cooler box, try to limit how often you open the lid because every peek lets warm air in and cool air out.

Contrary to what you might think, it’s best to not drain the melted ice water as scientific experiments have proven that not draining helps insulate the remaining ice for longer. However, the flip side to this is that food products and canned drinks will end up bobbing about in iced water so make sure that any meats are well sealed lest the packaging is breached by water.

With thoughtful packing, minimal lid-lifting and a shady position, a decent-quality passive cooler box will keep your essentials chilled for a couple of days, a higher-end model like the Coleman Pro we’re looking at here should retain a decent amount of ice for about four days and a premium rotomoulded model from the likes of YETI will retain ice for up to a week or more.

Design and features

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Always keep your cooler in the shade

Robust hinges and a thick seal ensure firm closure

Thanks to the nylon handles, this cooler is very easy for two to carry

The all-important drain plug – just don't use it on the kitchen floor!

Coleman has pulled out all the stops for this Pro model. Cast from robust recyclable High-Density Polyethylene (HDPE) thermoplastic, insulated using polyurethane foam and lined with an antibacterial layer, the Pro 45 QT is built like a brick outhouse with robust hinging, a firm rubber seal, a brilliant metal latch that clips down with a reassuring click, sturdy side grips for hoisting it out of the car and two fantastic nylon strap handles for really easy two-person carrying. The lid also serves as a seat.

Unlike most YETI products that are available in a multitude of colours (see also: best YETI coolers), this model is mostly only available in off-white (at least here in the UK) though I have spotted a pale blue option on Amazon.

However, I happen to think this arguably bland colour is not only aesthetically pleasing but also an advantage when positioned in direct sunshine since much of the sunlight is reflected. I also love the matt finish which helps fend of inevitable scuffs during transport.

As the moniker suggests, the Coleman Pro 45 QT has a capacity of 45 quarts which equates to 42.5 litres or up to 74 standard 330ml/12 oz cans without ice. That’s a very decent amount of space for a family of four and more than enough meal estate for a group picnic, but bear in mind that a lot of the interior will also be taken up with ice. According to Coleman, this model sports a commendable ice retention period of four days and that makes it a perfect choice for a long weekend away.

With a weight of 7.9 kilos, the Pro 45 QT isn’t too heavy for one person to carry, even when filled. However, those strap handles I mentioned earlier make it a veritable breeze for two people to carry a fair old distance without the unit banging against their legs.

At 63cm in length, 42cm in depth and 43cm in height, this model is on the large side so it’s not a practical model for a small hatchback car unless you’re travelling light. However, it is a perfect size for any SUV or estate car and ideal for a US-style pickup truck (the unit is fitted with four grippy rubber feat and tie-down holes in the lid for safe transport). Moreover, it’s relatively shallow rectangular shape also makes it easier to rummage about for products at the bottom of the cooler without freezing your whole arm in the process.

One especially handy facet with this model is that it also comes with a large draining plug and this makes a world of difference since it allows you to drain away all that iced water without having to tip the whole thing on its side.

Performance

I tested this passive cool box on a three-day, four-person camping trip in Wales in high ambient temperatures of around 27˚C (80.6˚F) and it performed like a trouper. I actually had a choice between taking this Pro model or the much smaller Coleman 28 QT Convoy I reviewed in 2024 and, although the Pro took up a lot more space in our Honda CR-V, I am so glad I managed to fit it in with the surfeit of other camping accoutrements I took along because it held twice the amount of food and drink and proved an invaluable asset in every regard.

I confess to not having heeded advice about loading the Coleman Pro with a 2:1 ice ratio, as we had a lot of food and drink to transport. Instead, I just threw in two one-kilogram bags and a half-dozen small ice packs. The amount of loose ice was just enough to fill a double-layer on the bottom, way below the advised amount.

I then filled it with 12 small canned drinks, eight standard canned drinks, two litre bottles of Aqua Carpatica (the best spring water money can buy), 10 chicken legs, 12 chicken wings, four burgers and 10 sausages from the local farm shop, a packet of bacon, some tomatoes, a cucumber, a litre of milk and packets of couscous, coleslaw and salsa dip. And that was just for lunch! Only kidding.

I also made a point of keeping the Pro out of the sun near the entrance of my family-sized Quechua Air Seconds 5.2 tent to maximise its performance.

By the time we reached the campsite midday Friday, the ice was still fully formed and the drinks were freezing cold. By Saturday late afternoon, about an inch of iced water had developed, but everything was still perfectly chilled.

By the time we got home on Sunday evening, almost all of the ice had melted, but the remaining drinks were nearly as cold as they were on day one. I call that a result and have no doubts that, had I heeded advice and loaded the cooler with a few more kilos of ice, the Coleman Pro would have retained most of it for the advertised four days. However, I just wouldn’t have had as much space for the foodstuffs. Swings and roundabouts spring to mind.

This cooler has now become one of my main camping essentials and I can’t recommend it enough, especially since it’s about half the price of the similar-sized YETI Roadie 48 I also previously reviewed. However, if it was just two of us going on a weekend trip, a one-day festival or a picnic, I might consider taking the smaller Coleman 28 QT Convoy instead.

Verdict

If you’re in the market for a large, robust 42-litre passive cooler that retains ice for up to four days, the Coleman Pro 45 QT is a top pick. It’s spacious enough for group trips, tough enough for the back of a pickup and clever enough to include essentials like a two-person strap handle and an all-important drain plug. Whether you’re at a campsite or festival, on a picnic, a boat or just entertaining in the garden, this keenly-priced cooler stays reliably chilled whatever the weather. Top marks.