The best travel backpack for carry-on use in the UK starts with the bag allowance on your actual booking. For a single free underseat bag, choose the Cabin Max 24L and its stated 40 × 30 × 20cm shape. If you have paid for a larger overhead bag, the Cabin Max 40L uses the extra allowance. The Osprey Daylite 26+6L is a lighter, more adaptable choice for rail trips and flights with roomier limits; the tomtoc Navigator-T66 gives laptop travellers better access. None is universally “airline approved”: the carrier, fare and packed dimensions decide what you can take.
Our top 4 picks
Cabin Max 24L 40 × 30 × 20cm
Best free-bag fit
The clearest choice for a Ryanair-sized underseat allowance.
Osprey Daylite 26+6L
Best flexible pack
A comfortable day-to-travel design with a useful 6L expansion.
tomtoc Navigator-T66 40L
Best laptop layout
Separate tech access and a suitcase-style main opening.
Cabin Max 40L 55 × 40 × 20cm
Best overhead space
A rectangular pack sized for Ryanair’s paid overhead allowance.
In this guide
- Comparison at a glance
- The four best travel backpacks
- Cabin rules before you choose
- How to measure and pack
- Comfort and organisation
- How we chose
- The bottom line
- Frequently Asked Questions
Comparison at a glance
| Backpack | Best for | Listed size | Capacity | Key limit |
|---|---|---|---|---|
| Cabin Max 24L 40 × 30 × 20cm | Best free-bag fit | 40 × 30 × 20cm | 24L | Check the packed bag still fits the sizer. |
| Osprey Daylite 26+6L | Best flexible pack | 43 × 33 × 16cm unexpanded | 26+6L | Too wide for Ryanair’s free-bag limit. |
| tomtoc Navigator-T66 40L | Best laptop layout | About 52 × 33 × 23cm | 40L | Too deep for Ryanair’s 20cm overhead limit. |
| Cabin Max 40L 55 × 40 × 20cm | Best overhead space | 55 × 40 × 20cm | 40L | A full-size overhead bag, never an underseat pick. |
Dimensions are stated product sizes, rather than a promise that a stuffed pack will fit an airport sizer. The Osprey measurement is for its unexpanded form; expansion adds roughly 5cm of depth. The tomtoc’s listed dimensions convert from the manufacturer’s inches, so allow a little margin when measuring your own bag.
The four best travel backpacks
1. Cabin Max 24L: best free-bag fit
This is the clearest choice when a Ryanair booking includes only the small personal bag. Its stated 40 × 30 × 20cm shape matches that allowance, and the rectangular main compartment makes better use of the permitted space than a narrow daypack. Compression straps, a bottle pocket and a rear trolley sleeve make it practical beyond the flight.
Pack with the sizer in mind. A soft bag can bulge beyond its nominal 20cm depth when every pocket is full, and external bottles count towards the outline. The 24L label is a useful guide to capacity, while the actual packed measurements are what matter at boarding. This is the bag for a light weekend or a carefully packed longer trip, rather than bulky footwear and several outfit changes.
- Choose it if: you want to use a 40 × 30 × 20cm underseat allowance.
- Bear in mind: the compact allowance still governs once the bag is full.
2. Osprey Daylite 26+6L: best flexible pack
The Daylite makes sense for a traveller who wants one backpack for trains, a city break and flights with a suitable cabin allowance. Osprey lists a 43 × 33 × 16cm unexpanded body, about 0.84kg empty, a ventilated AirScape back panel and an expansion zip that adds 6L. The layout has a tech sleeve and two bottle pockets. Its slimmer unexpanded shape is easier to live with between journeys than a full 40L box.
The width is the important catch: 33cm exceeds Ryanair’s 30cm free-bag limit. Expansion also increases depth. Treat the 26+6 figure as packing flexibility, not a licence to exceed the allowance on your ticket. If you often change airline, measure the loaded bag before each trip.
- Choose it if: comfort and a flexible daily-use size matter more than maximum packing volume.
- Bear in mind: check the airline allowance against the unexpanded or expanded pack you will actually carry.
3. tomtoc Navigator-T66 40L: best laptop layout
The tomtoc separates a laptop compartment from its suitcase-style main opening. That is useful when a laptop comes out at security while clothes stay packed. The product information describes space for a laptop up to 17 inches, accessible front and top pockets, compression straps and a luggage pass-through. Its listed 20.47 × 12.99 × 9.06 inches convert to roughly 52 × 33 × 23cm.
That 23cm depth is too much for Ryanair’s 20cm large-cabin limit, even before allowing for overpacking. It sits within easyJet’s published 56 × 45 × 25cm large bag dimensions, provided that allowance is included or added to your booking. A laptop, charger and clothes can make a 40L bag heavy, so use the sternum and hip straps when walking between stations. The panel-style opening is better for orderly packing than reaching down through a narrow top opening.
- Choose it if: you carry a large laptop and have an appropriate overhead-bag allowance.
- Bear in mind: it is not a Ryanair 20cm-deep cabin-bag solution.
4. Cabin Max 40L: best overhead space
At a stated 55 × 40 × 20cm, this Cabin Max is designed around the larger Ryanair cabin-bag rectangle. It gives you far more packing space than the 24L version without the wheels and rigid shell of a suitcase. The broad front opening, external compression straps and trolley sleeve suit simple clothes-and-toiletries packing.
This is an overhead-size choice for a booking that includes the larger cabin bag; it exceeds Ryanair’s free personal-bag allowance. A 40L bag can also become uncomfortable when loaded heavily; check your fare’s weight limit and lift it as you would into an overhead locker. It is a practical way to maximise an allowance, while the Osprey offers a more compact everyday shape.
- Choose it if: you have the larger cabin allowance and want a simple rectangular pack.
- Bear in mind: use the paid/included overhead-bag allowance, not the free underseat one.
Cabin rules before you choose
Airlines separate a small bag under the seat from a larger bag in the overhead locker. The distinction is tied to your booking, not a product-page badge. Ryanair’s current bag policy gives a 40 × 30 × 20cm small personal bag; its Priority & 2 Cabin Bags option adds a 55 × 40 × 20cm bag up to 10kg. easyJet’s cabin guidance lists a 45 × 36 × 20cm small bag for everyone and a 56 × 45 × 25cm large bag where the fare or an add-on includes it.
Check the operating airline’s policy again when booking and before departure. A connection or codeshare can change the relevant rule. Check all three exterior dimensions with pockets filled and straps tucked in, and weigh the complete pack where your allowance has a weight cap. The Cabin Max 24L is sized for the Ryanair free-bag rectangle. The 40L Cabin Max is for its larger cabin allowance. The Osprey and tomtoc need their own fit check against the fare you have.
How to measure and pack
Measure the packed bag
Fill the backpack with the load you expect to fly with, close every compartment and place it against a wall. Measure height from base to highest handle, width at the fullest pocket and depth from back panel to the most protruding front pocket. A flexible bag can pass a ruler test when empty and fail a sizer once full. Leave a little margin if you plan to bring home purchases.
Pack for access and balance
Place heavy items close to your back and keep documents, medication and travel liquids easy to reach. A packing cube can separate clothes from cables without adding much structure. Our rucksack packing guide explains load placement in more detail; the same balance principle helps on a long airport walk. For a compact bag, choose the shoes and outer layer first, then see how much space remains. The rucksack size guide helps translate litres into realistic kit.
Comfort and organisation
A travel pack earns its place over a suitcase when stairs, train changes and uneven pavements are part of the trip. Shoulder-strap shape, the back panel and the ability to keep a heavy laptop close to your body matter more than another pocket. The Osprey has a less boxy shape than the full-size 40L options; the tomtoc gives a clearer laptop workflow. Try the loaded weight at home before committing to a long transfer on foot. Our rucksack fitting guide covers strap adjustment and where load should sit.
Choose organisation around the items you actually retrieve in transit. A dedicated laptop sleeve is useful when you work between flights. A big, open clothing compartment suits short holidays. Too many small pockets can hide the one thing you need at the gate. If wet weather is part of a rail-and-walking journey, use a liner or cover for vulnerable contents; water-resistant fabric is not the same as a waterproof pack. See our backpack waterproofing guide for practical options.
How we chose
The useful split is between underseat size, flexible daily carry, laptop access and overhead volume. Compare the listed exterior dimensions and carrying features with your booking, then measure your loaded pack before flying. The four bags answer those different travel needs. A litre figure never establishes cabin fit.
For a general introduction to backpack types and fit, see our backpacks buying guide. If you mostly walk trails rather than travel between cities, our day-pack comparison is the more relevant shortlist.
The bottom line
For a free Ryanair-sized personal bag, pick the Cabin Max 24L and keep its packed outline within 40 × 30 × 20cm. With a larger overhead allowance, the Cabin Max 40L makes the most of a 55 × 40 × 20cm rectangle. Choose the Osprey Daylite 26+6L when comfort and flexible everyday use matter most, or the tomtoc Navigator-T66 when a large laptop needs its own access. Check the booking and measure the filled bag before travelling; the wrong fare allowance is a more expensive mistake than choosing between two good backpacks.
Frequently Asked Questions
What size backpack fits Ryanair’s free bag allowance?
Ryanair currently lists 40 × 30 × 20cm for its small personal bag. The Cabin Max 24L has those stated exterior dimensions; measure it again when packed, including pockets and handles.
Can I take a 40L backpack on Ryanair?
A 40L pack may travel in the cabin when its packed dimensions and weight fit the allowance on your booking. The 55 × 40 × 20cm Cabin Max 40L is an overhead-size option for Priority & 2 Cabin Bags, not the free small-bag allowance.
Is the Osprey Daylite 26+6L a free Ryanair bag?
Its listed unexpanded width is 33cm, above Ryanair’s 30cm free-bag limit. It can suit a different airline or a larger allowance; expansion increases its depth, so check the packed size.
Will the tomtoc 40L fit an easyJet cabin allowance?
Its listed size is about 52 × 33 × 23cm, within easyJet’s published large-cabin rectangle of 56 × 45 × 25cm. That larger allowance must be included with your fare or added to the booking, and the packed bag still needs to fit.
Do airline limits include backpack handles and pockets?
Measure the full packed exterior, including a raised handle and filled outer pockets. Airlines can check the whole bag in a sizer, so a nominal product dimension alone is not enough.
Is a travel backpack better than a cabin suitcase?
A backpack is easier on stairs and through train changes; a wheeled case removes weight from your shoulders on smooth ground. Choose around your transfers, the load you can carry and the exact bag allowance.