STM Prime vs. Tortuga Outbreaker Daypack
Two carry-on travel backpacks, compared spec for spec.
STM Prime
| Capacity | 15 L |
| Weight | 0.7 kg |
| Dimensions | 42×26×13 cm |
| Airline fit | 96% |
| Price | $80 |
Feature by feature
| STM Prime | Feature | Tortuga Outbreaker Daypack |
|---|---|---|
| Storage | ||
| N | Compression | N |
| None | Expanded Capacity | None |
| 0 | Opening | 0 |
| top | Passport | front |
| N | Passthrough | N |
| Carry | ||
| Y | Backpack | Y |
| N | Hip Belt | N |
| Y | Sternum Strap | removable |
| Inside | ||
| 13in | Laptop | 15in |
| 2 | Main Compartments | 2 |
| N | Organizer | N |
| Outside | ||
| × | Hard Shell | × |
| N | Rain-fly | N |
| 2, side | Water Bottle Holder | 2, side |
| Y | Water Resistant | Y |
| Material | |
| Polyester | X-Pac waterproof sailcloth |
Tortuga Outbreaker Daypack
| Capacity | 21 L |
| Weight | 0.5 kg |
| Dimensions | 43×28×17 cm |
| Airline fit | 96% |
| Price | $125 |
Key differences between the STM Prime and Tortuga Outbreaker Daypack
- Passport pocket: Top on the STM Prime; Front on the Tortuga Outbreaker Daypack.
- Sternum strap: Yes on the STM Prime; Removable on the Tortuga Outbreaker Daypack.
- Laptop sleeve: 13in on the STM Prime; 15in on the Tortuga Outbreaker Daypack.
Both have: backpack straps, water bottle pockets, water resistant.
Which airlines take each bag as a carry-on
We checked both bags against the carry-on size limits of 189 airlines. 181 accept both. Every airline that takes one takes the other.
STM Prime vs. Tortuga Outbreaker Daypack: which should you pack?
The Tortuga Outbreaker Daypack carries 6L more than the STM Prime (15L vs. 21L), while the Tortuga Outbreaker Daypack is the lighter pack at 0.5kg (vs. 0.7kg). For carry-on flexibility, the STM Prime fits 96% of the airlines we track — the higher of the two. If you prioritise packing volume, choose the Tortuga Outbreaker Daypack; if you want to travel lighter, the Tortuga Outbreaker Daypack is the better call.