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Therm-a-Rest MondoKing 3D Review

Our favorite option with well-designed valves and a pump sack for easy inflation
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Therm-a-Rest MondoKing 3D Review (The surface is marked with a unique ridge pattern that does not inhibit comfort in any way. The cover is quiet and soft.)
The surface is marked with a unique ridge pattern that does not inhibit comfort in any way. The cover is quiet and soft.
Credit: Laurel Hunter
Price:  $275 List
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Manufacturer:   Therm-a-rest
By Laurel Hunter ⋅ Review Editor  ⋅  Apr 21, 2023
87
OVERALL
SCORE


RANKED
#1 of 16
  • Comfort - 40% 10.0
  • Ease of Use - 20% 9.0
  • Warmth - 20% 8.0
  • Versatility - 10% 7.0
  • Packed Size - 10% 6.0

Our Verdict

The Therm-a-Rest MondoKing 3D is a fantastically comfortable mattress featuring four inches of plush foam comfort. This mattress does a stellar job insulating you from the cold ground while supporting your pressure points — no matter your preferred sleeping position. The TwinLock valves ensure very simple inflation and deflation, and the included pump sack means you won't pass out from blowing it up. The current MondoKing is lighter than previous versions, and while it also has a lower insulation value, we sure didn't notice the difference. Overall, if you can swing the cost, we don't foresee you being disappointed after the great nights of sleep this mat will encourage. See it rated versus top competitors in our camping mattress review.
REASONS TO BUY
Warm
Comfortable
Easy to inflate
REASONS TO AVOID
Large packed size
Pricey
Editor's Note: This review was updated on April 21, 2023, to ensure we still stand by all findings and to add video from our Spring testing session.

Compare to Similar Products

 
Awards Editors' Choice Award
Best Overall Camping Mattress
Best Buy Award
Best Bang for the Buck
Top Pick Award
An Exceptionally Comfortable Mat
Top Pick Award
Excellent, Self-Inflating Comfort
Best Buy Award
Great Lightweight Value
Price Check Price at REI
Compare at 3 sellers
$179 List
$179.00 at REI
$239.95 at REI
Compare at 3 sellers
$249.95 at REI
Compare at 3 sellers
$179.95 at Backcountry
Compare at 2 sellers
Overall Score Sort Icon
87
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71
Star Rating
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Bottom Line A high scorer in our tests, this pad is warm and comfy and easy to inflateAll the favorite features we love from a camping mat at a great priceWith four inches of foam you can't go wrong, unless you don't have space to store itFoam car camping comfort that packs into a smaller and lighter package than its peersComfortable enough for car camping and backpacking, this is a versatile and packable mattress
Rating Categories Therm-a-Rest MondoK... REI Co-op Camp Drea... Exped MegaMat 10 NEMO Roamer Therm-a-Rest NeoAir...
Comfort (40%)
10.0
10.0
9.0
8.0
6.0
Ease of Use (20%)
9.0
9.0
8.0
9.0
9.0
Warmth (20%)
8.0
8.0
9.0
7.0
5.0
Versatility (10%)
7.0
6.0
7.0
8.0
10.0
Packed Size (10%)
6.0
6.0
5.0
7.0
9.0
Specs Therm-a-Rest MondoK... REI Co-op Camp Drea... Exped MegaMat 10 NEMO Roamer Therm-a-Rest NeoAir...
R-Value 7 6.6 8.1 6 3.7
Thickness 4.3 in 4.0 in 4.0 in 4.0 in 4.0 in
Length 80 in 78 in 78 in 78 in 77 in
Width 30 in 32 in 30 in 30 in 30 in
Weight 5.3 lb 6.4 lb 6.1 lb 5.9 lb 2.3 lb
Packed Size 9 in x 32 in 11 in x 30 in 9 in x 33 in 16 in x 10 in 12 in x 6 in
Type Self inflating, inflation sack Self inflating, inflation sack Self inflating Self inflating Pump inflation
Test Model XXL XL LXW XL, XWide XLarge
Bed Material Polyester Recycled polyester 50D polyester with TPU polyether film laminate 75D polyester Polyester
Valves TwinLock Two valves Two valves Three valves TwinLock
Accessories Stuff sack Air pump, pillow Mini pump, stuff sack, repair kit and manual Stuff sack, pump sack, repair kit Stuff sack, pump, pump sack

Our Analysis and Test Results

The MondoKing 3D is exceptionally comfortable and warm. Just keep in mind that it's large when packed (like most of the foam mattresses in our review), but it is just slightly easier to inflate and deflate than almost all the others we've tested.

Performance Comparison


therm-a-rest mondoking 3d - plenty comfortable and plenty of surface area to sprawl, we love the...
Plenty comfortable and plenty of surface area to sprawl, we love the MondoKing.
Credit: Laurel Hunter

Comfort


Compared to your standard inflatable sleeping pad or basic air mattress, using the MondoKing 3D is bonafide luxury camping. Vertical sidewalls mean you can utilize the entire 30-inch width and 80-inch length to spread out and sleep like a large king starfish. While this may feel indulgent for camping, it is quite lovely not to feel like you are in danger of rolling off the edge of the mattress. These generous dimensions also provide room for your dog to snuggle nearby.


No matter your preferred sleeping position, the four-inch foam core of the MondoKing can easily be adjusted to perfect firmness with the separate one-way valves (one for “in,” one for "out"). Because it is easier to release a little air with a simple twist of the conveniently labeled “out” valve than it is to add air on the fly, we recommend adding extra air before you settle in for the night. At that point, you can release air, as necessary, for the perfect level of comfort.

The MondoKing uses StrataCore Foam, essentially a thermal foam core sandwiched between ridges of foam and air. This gives the surface a unique wave-like texture and makes it much easier to roll up. It also offers a substantial weight reduction from the previous version of this mattress. We did not notice the ridges at all when using the MondoKing, and the soft polyester cover provides a non-slippery, non-sticky place to lay a cheek that is both breathable and quiet to sleep on top of. Many of the mattresses we tested are comfortable, but this is one of the best.

therm-a-rest mondoking 3d - the therm-a-rest mondoking, with four inches of insulating foam, is...
The Therm-a-Rest MondoKing, with four inches of insulating foam, is warm enough to sleep on in your vehicle, where metal can be colder than the ground.
Credit: Laurel Hunter

Ease of Use


Probably the greatest improvement to the MondoKing from older iterations is the new and improved valves. They are located on each of the bottom two corners of the mat and are clearly labeled IN and OUT. They are noticeably larger than the old two-way valve, meaning more air can be moved through them, and since they are one-way, they are easier to use.


The MondoKing can still be blown up by mouth, but the stuff sack doubles as an inflation sack, meaning you can inflate without getting lightheaded. The sack snaps onto the valve, and then you blow lightly into the bag (or even better, catch a breeze) and then roll up the sack to push air inside. We can't quantify that it is three times faster than the old system, as Therm-a-Rest claims, but this system is very easy to use. For the initial inflation, we allowed the mattress to self-inflate for about 20 minutes. Then, using only the pump sack, it took about two and a half minutes to fully inflate.

Easy inflation of the Therm-a-Rest MondoKing using the stuff sack.
Credit: Laurel Hunter

The deflation valve allows air to move quickly out of the mattress. After that, the foam takes some smashing to roll it small enough to fit in the storage sack. However, the one-way deflation valve does not let air in, meaning it is just a matter of rolling once to get most of the air out and then a second roll to squish everything tight.

The storage bag doubles as an inflation sack and snaps onto the...
The storage bag doubles as an inflation sack and snaps onto the intake valve for easy use.
The deflate valve opens up when air is pushed out and closes up when...
The deflate valve opens up when air is pushed out and closes up when it isn't, making deflation a much easier process.

Warmth


The MondoKing has an R-value of 7, somewhat lower than the older version, which we are guessing is related to the new ridged foam interior. R-value tells you the insulating power of any given sleeping pad or camping mattress, giving you an idea of how cold of a surface you could comfortably sleep on without that coldness seeping through to your body. To winter camp, it's generally recommended to use a sleeping pad or mattress with an R-value of at least 4.


We camped at 18 degrees Fahrenheit with the MondoKing and had zero complaints. If you are heading off for a sub-arctic adventure, there are a few mats in this test that are rated higher for insulation, but for four-season camping in the lower 48 states, the MondoKing should be plenty toasty. It's also just as important to note that, unlike the cold-temperature rating of a sleeping bag, having a camping mattress with an R-value this high won't make you pour sweat in hot weather. This is a solid four-season camping companion.

Versatility


Based on the overall size and weight of the MondoKing 3D, this isn't the camping pad you would take on a backpacking trip. At 5.27 pounds, you won't want to carry this mattress too far from your car or garage. However, it is worth noting that the XXLarge version that we tested is lighter than the old version while being considerably larger.


While our testers quite adored the large surface area, two of these pads in size XXLarge will not fit in the average two-person tent, which is around 50-55 inches wide. The Large size is 25 inches wide, so two of those should fit. We suggest you check this against your own personal tent width, as tent styles and sizes vary. If you are car camping in full glory, however, you may very well have a much larger tent, in which case, why not go all out for maximum surface area?

therm-a-rest mondoking 3d - it is not tiny! but there is a handy carrying strap.
It is not tiny! But there is a handy carrying strap.
Credit: Laurel Hunter

Packed Size


When packing the car for a weekend of camping, the MondoKing isn't too large to bring and more than makes up for its size with its comfort. While we wouldn't be stoked to pile seven of them in the back of the van, the space it takes up is comparable to the other highly comfort-rated mattresses in this review.


Value


The MondoKing 3D is on the more expensive side of the self-inflating camping mattresses we tested. Despite being a decent chunk of change to throw down on a camping mattress, we think you'll find the comfort and ease of use to be well worth the dough.

therm-a-rest mondoking 3d - the inflation sack makes all the difference in ease of set-up.
The inflation sack makes all the difference in ease of set-up.
Credit: Laurel Hunter

Conclusion


This pad combines a high level of comfort and an excellent valve system, helping it eke out the top spot in our lineup. The MondoKing 3D is an ideal all-around camping solution, and we would happily recommend it to both our dirtbag, live-out-of-my-van friends, as well as our hard-to-please, princess-and-the-pea family members.

Laurel Hunter