UNDERSEAT PRO 17.5″ Travel Backpack Review

Even fully packed, we have no problem fitting the UNDERSEAT PRO 17.5″ Travel Backpack under an economy-class seat. However, we wish its straps were beefier.

Our Verdict

7.1 /10
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  • Dimensions fit personal item size of most budget airlines, so you can pack a lot of gear
  • Fairly easy to fit underneath airline seats, even if you do overpack it
  • Has plenty of pockets, internally and externally, for organizing gear


  • Exceeds budget airline size requirements if overstuffed, which is fairly easy to do
  • Top handles get in the way of compartment access
  • You can feel your laptop on your back when it's in the sleeve at the back

Technical Details

85 %

Carry-on Compliance

View 123/145 Airlines

29 %

Like the Look

Polled on Instagram

  • Capacity


  • Weight (lb)

    2.42 lb (1.1 kg)

  • Dimensions

    18 in x 14 in x 8 in (45.7 x 35.6 x 20.3 cm)

  • Notable Materials

    Polyester, YKK Zippers, Unbranded Hardware, Unbranded Zippers

  • Manufacturing Country


  • Warranty Information

    Shipping & Returns

Full Review

Budget airlines are some of the strictest we’ve ever flown with when it comes to the bags you bring aboard. You name it: whether it’s your personal item, a carry-on, or a checked bag, you can bet they’re keeping an eye on you. And if they sense that your bag is too big, they’ll even kindly but firmly ask you to put it in a measuring bin to make sure it complies with whatever size requirement your ticket covers. Fortunately, some brands make it a point to have their bags comply with such rules, as arbitrary as some may seem.

UNDERSEAT PRO 17.5″ Travel Backpack Walking
UNDERSEAT PRO 17.5″ Travel Backpack | The brand name lays it on thick.

In this review, we’ll be taking a look at UNDERSEAT PRO’s 17.5” Travel Backpack. Coming in at 18 in x 14 in x 8 in, the brand claims it fits most popular airlines’ requirements regarding a personal item. However, there is some nuance; based on our testing, this bag isn’t entirely guaranteed to pass every size inspection. Also, take note that there is a version of this bag sans the laptop compartment and with a slightly different pocket layout—a version that we’ll bring up as a point of comparison wherever relevant. So, without further ado, let’s dive in and check this bag out.

External Components

For something that’s ostensibly a travel backpack, this bag looks a lot like a daypack. Anyone familiar with the classic styling of Fjallraven will see what we mean. You have a heritage-style logo at the front, a pair of long tote-style handles at the top, and a squared-off shape, which we find a playful aesthetic choice when paired with the former qualities. If not for its large size, this would pass for a bag that you can totally carry around daily without looking like you’re packing days worth of gear.

UNDERSEAT PRO 17.5″ Travel Backpack Brand
UNDERSEAT PRO 17.5″ Travel Backpack | The build and materials feel okay.

Looks aside, the bag’s construction feels “okay.” There’s nothing super structured or exceptionally robust, but it emerged unscathed after being shoved in and out from underneath our seats. Our biggest gripe is that there are a few loose threads scattered around, plus a really flimsy-feeling carabiner that came included. Otherwise, the polyester fabric proved adequate for protecting the gear inside, even though it’s a bit on the softer side.

The first external feature that drew our attention was the set of pen loops in the bag’s upper right side. We can’t remember the last time we’ve seen external mounting specifically for pens, but it’s not entirely out of place, either. Go through enough airports in your life, and you’ll learn that they never run out of forms and slips for you to fill out, so having a pen ready is quite handy. That said, we never really had to use it since most of the airports we go through already provide pens whenever they hand out forms. In other words, these pen slots aren’t particularly useful to us.

UNDERSEAT PRO 17.5″ Travel Backpack Side Loops
UNDERSEAT PRO 17.5″ Travel Backpack | Might be useful if you’re always being asked for your autograph.

On the other side is a simple but large water bottle pocket. The front side is made out of fabric, while its back half is mesh, which helps condensation from your bottle evaporate. For grip, there’s a cinch cord that keeps your bottle inside. We use a relatively modest 22-ounce insulated bottle, and the combination of the cinch cord and the fact that the pocket almost completely swallows it makes sure it stays in place.

Larger travel water bottles fit for sure. There’s even a loop with the aforementioned carabiner at the top if your bottle’s handle reaches that high and you want to secure it. Again, the carabiner is really flimsy, almost like an afterthought. Its gate sometimes jams in place when you push it in, it wiggles, and the overall build just feels thin. We recommend using your own trusted carabiner.

UNDERSEAT PRO 17.5″ Travel Backpack Water Bottle Carabiner
UNDERSEAT PRO 17.5″ Travel Backpack | The carabiner’s flimsy build quality leaves a lot to be desired.

Up at the top are the twin tote-style handles. Having two handles instead of a centralized one creates a more balanced carry, which we like. The wrap that keeps the handles together also provides some padding for better comfort. The main drawback is that the handles both go over the main compartment and laptop compartment, meaning you have to decouple them each time you need to open them.

This bag’s main “external” feature is its compliance with most popular airlines’ personal item size requirements. A quick warning, though: Size requirements usually vary from airline to airline, and what bag you can bring depends on other factors, like what’s included in the ticket you’ve bought. For example, some basic fares let you bring a personal item, but others may include an additional carry on, each with its own size limits. That said, the key thing to remember about this particular bag is that, regardless of those arbitrary rules, we had no trouble getting it under our seats without fail.

UNDERSEAT PRO 17.5″ Travel Backpack Hor
UNDERSEAT PRO 17.5″ Travel Backpack | It fits underneath most airline seats.

Now for the harness system. The setup here is fairly basic, even for a travel backpack with a modest 25-liter capacity. You get what appears to be adequately padded shoulder straps with a mesh layer underneath for breathability. The sternum strap is mounted on a rail, offering great adjustability, and uses a simple side-release buckle. The back panel is plain fabric with a built-in zippered pocket, but that doesn’t automatically make it uncomfortable.

UNDERSEAT PRO 17.5″ Travel Backpack Back Pocket
UNDERSEAT PRO 17.5″ Travel Backpack | A simple harness system.

All that said, these prove inadequate in terms of comfort once you fully load the bag like we have. The padding isn’t dense or cushioned enough to handle the total weight, necessitating the use of the sternum strap. There are loops at the bottom where you can mount a hip belt. However, that’s a separate purchase, so we won’t factor that into this review.

Fit Notes

UNDERSEAT PRO 17.5″ Travel Backpack Side By Side
Left: Lauren Maternowski, Height: 5’6” (168 cm), Torso: 16.5” (42 cm) | Right: Eric Hergenreder, Height: 6’0″ (183 cm), Torso: 18.5” (47 cm)

Unfortunately, the shoulder straps don’t do a very good job of spreading out the bag’s weight. We know it sounds almost silly to expect a pair of straps to magically make a bag feel lighter since that weight has to apply force somewhere. However, when you’ve tested as many bags as we have, you’ll learn that a good harness system can employ a few tricks to achieve this, pulling the pack’s weight forward to lessen the feeling of sagginess.

UNDERSEAT PRO 17.5″ Travel Backpack Strap
UNDERSEAT PRO 17.5″ Travel Backpack | The straps don’t feel adequate for the bag’s overall size.

As we’ve mentioned, using the sternum strap is necessary to lessen that saggy feel, but it’s not really enough. The overall carry still feels cumbersome, so we think using a hip belt is ideal. It’s also worth noting that we could feel the device in the laptop compartment bulging out near the lower back.

Inside The Backpack

We’ll discuss the laptop compartment a bit later in this section. For now, let’s take a look at more secondary pockets, starting with the hidden one built into the back panel. Okay, it doesn’t seem especially hidden when you look at it, but it’s quite hard to reach once you’re wearing the bag. Consequently, you don’t want to put anything too bulky in this pocket since it rests right against you. It’s best for important travel documents, which are usually flat anyway, like a passport, spare cash, credit cards, and plane tickets.

UNDERSEAT PRO 17.5″ Travel Backpack Front Pocket
UNDERSEAT PRO 17.5″ Travel Backpack | It’s a wide and deep pocket, but there’s not much horizontal depth.

Next up is the pocket in front of the bag. Appearance-wise, it’s large, so you’d think we could just throw in whatever gear we wanted. That’s not the case, though, as it is wide and deep; it’s slim on horizontal depth, especially when the rest of the bag is fully packed out and bulging. At most, we could fit a large pack of gum and a smartphone. You can still squeeze in otherwise bulky items like a pair of winter gloves or a buff, but you’ll have to fold them carefully to make access easy.

On the right side of the bag are two smaller zippered pockets. Whereas the front pocket is too large and deep for everyday carry items, these feel just the right size. Toss in a set of keys, wireless earbuds, a minimalist wallet, or even some candy, and you won’t have to reach elbow-deep to retrieve them. It’s worth noting that the front side of these pockets bears the underlying TPU coating where you’d expect them to use fabric liner. It’s great to know there’s some weather-proofing going on, but it does feel a bit barebones to see that.

UNDERSEAT PRO 17.5″ Travel Backpack Side Pockets 2
UNDERSEAT PRO 17.5″ Travel Backpack | These are your quick-access pockets.

One of this bag’s weakest points is the laptop compartment. On paper, it checks all the right boxes. The laptop sleeve is padded, there’s plenty of room for a large accessory like a travel keyboard, and it also has a zippered pocket for additional tech accessories—a modest setup but otherwise standard. Our main issue is that actually having a laptop inside the sleeve affects comfort. You can feel the bottom edge of your computer poking out from the back panel. It’s worth noting that taking the laptop out but having relatively bulky charging adapters in the zippered pocket doesn’t affect comfort in the same way. Instead, we put the 13-inch MacBook we were using in the main compartment.

It’s worth noting that there’s another version of this bag that doesn’t have a dedicated laptop compartment. This eliminates the whole comfort issue but with the tradeoff of not having anywhere to put your laptop except inside the document sleeve in the main compartment’s back side.

UNDERSEAT PRO 17.5″ Travel Backpack Laptop Charger
UNDERSEAT PRO 17.5″ Travel Backpack | It also fits a 16-inch MacBook Pro like this dummy one.

The main compartment opens fully clamshell-style to reveal a huge bucket space. The first feature you’ll notice is the pair of hold-down straps, a standard feature on many travel bags. It’s particularly handy on the 17.5” Travel Backpack because it’s fairly easy to overpack. There’s so much room that we could shove in several loaded packing cubes. Unfortunately, this makes the bag expand beyond its standard dimensions, which, as you’ll recall, is designed to meet the personal item size requirements of popular airlines.

In terms of organization, there are a lot of pockets in the main compartment. Starting on the bucket side, you’ll find a total of six zippered mesh pockets for smaller items like toiletries, clothing accessories, and keys (there’s a small leash where you can attach a set). We recommend spreading your gear among these pockets to avoid over-packing just one of them. There’s also a sleeve at the back where you can store some documents. You could also use it to separate some clothing from the rest of your gear.

UNDERSEAT PRO 17.5″ Travel Backpack Empty Main
UNDERSEAT PRO 17.5″ Travel Backpack | There are a lot of pockets within the main compartment alone.

On the front side is another somewhat padded sleeve. This is our alternative laptop storage since the main one wasn’t comfortable. Fortunately, it also has a hook-and-loop tab like the main one, so it’s pretty much a secondary laptop sleeve, just in a different location. There’s even a zippered pocket just below where you can put additional tech accessories. The main drawback of using this to store your laptop is having to open the main compartment, which can potentially mess up the rest of your gear’s organization. It’s not too bad, though, since the hold-down straps do a good job of keeping things in order. By the way, this entire front-side layout is different in the laptop compartment-less version of this bag. In that version, there are instead two large zippered mesh pockets, which are quite easy to reach into even if you only open the main compartment zippers around the top.

UNDERSEAT PRO 17.5″ Travel Backpack Packing Cubes
UNDERSEAT PRO 17.5″ Travel Backpack | Use the hold-down straps to keep the size within airline limits.

Lastly, there is a pair of liner pockets just below the zippered pocket. These go fairly deep and would be useful for storing large (but still TSA-friendly) toiletry bottles. However, the stuff inside can slip out since the front side is relatively steeply inclined when fully opened.

Usage Timeline

Initial Usage

Condition: Excellent

  • Exact personal item measurements of some budget airlines—we love that it maximizes space and can save you cash
  • Lots of internal storage, though it seems kind of thrown together versus thoughtfully placed
  • Main compartment seems roomy for 25 liters
2 Weeks of Use

Condition: Excellent

  • Bag doesn’t fit budget airline size requirements if overstuffed—it makes the bag too round to fit in the tester bin, though it still fits under the seat
  • Materials still in great shape—a few loose threads, but nothing that worries us too much
  • Great organization if that’s what you’re into, though some pockets work better than others
By Lauren Maternowski
Created December 5, 2023 • Updated December 5, 2023
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