# Do you need a separate daypack on a one-bag trip?

> OneBag Kit · https://onebagkit.com/do-you-need-a-daypack-one-bag-travel/  
> Updated: 2026-10-06 · Published: 2026-10-06

Usually yes, but it can be small. A second, smaller bag for days out lets the main pack stay at the hotel: a packable daypack of about 10–20 liters, a sling, or a small backpack that doubles as the personal item on the plane. Pick it by what you carry on an ordinary day.

## Why bother with a second bag

Your main bag is for travel days. On a normal day out you want water, a layer, maybe a camera, and your phone and wallet, not a week of clothes. Many museums and some attractions also make you check large backpacks, and a big bag is tiring in crowds and on public transport.

## The four common setups

- **Packable daypack (about 10–20 L).** Folds into its own pocket and weighs very little. Fine for water, a jacket, and snacks. Thin straps and no structure, so it gets uncomfortable with a laptop or a heavy load.
- **Sling or crossbody bag (about 3–10 L).** Phone, wallet, power bank, sunglasses, maybe a small umbrella. Easy to swing to the front in crowds. Too small for a jacket and a big water bottle together.
- **Small backpack (about 15–25 L) as your personal item.** Comfortable all day and can hold a laptop. It doesn’t fold away, so if your fare allows only one cabin bag, it has to squeeze inside the main pack and costs real space.
- **No second bag.** A tote, a foldable shopping bag, or just pockets. Works for warm city trips where you carry little.

## How to choose

Lay out what you actually carry on a typical day out at home or on your last trip. Then ask:

- Does it need to hold a rain jacket or a warm layer? If yes, a sling is usually too small.
- Will you walk for hours with a camera or water? Then comfort matters more than packability.
- Is it also your personal item on the plane? Then check it against your airline’s under-seat size (see [personal item vs carry-on](https://onebagkit.com/personal-item-vs-carry-on/index.md)).
- Is it hot where you are going? A sling keeps your back cooler than a daypack.

Two combinations work well: a packable daypack plus a tiny sling, or a single 15–20 L daypack that also does airport duty.

## How much space it takes in the main bag

A packable daypack folds to about the size of a fist. A sling or small backpack doesn’t fold, so it costs real space. A 10 L sling packed inside a 40 L bag uses about a quarter of the volume, though you can fill the sling with socks or chargers so the space isn’t wasted.

On fares that include a personal item, the simplest move is to carry the small bag on the plane with your in-flight things and not pack it at all. On personal-item-only fares, the daypack is the whole luggage, and [packing with only a personal item](https://onebagkit.com/personal-item-only-packing/index.md) applies.

## Crowds and pickpockets

Wear a sling across the front in busy places, keep zips closed and facing your body, and keep the phone in an inside pocket rather than an outer one. A daypack with a zipped pocket against your back is harder to get into than a front pocket. None of this makes theft impossible; it just makes you a less easy target.

## Choose it with the main bag

If you are buying a new travel backpack, decide on the second bag at the same time, since it changes how much main-bag space you need. The deep guide on [how to choose a carry-on travel backpack](https://onebagkit.com/how-to-choose-a-carry-on-travel-backpack/index.md) covers the main bag; for rainy trips, see [what rain gear to pack](https://onebagkit.com/rain-jacket-or-umbrella-for-travel/index.md).

General packing guidance only. Bag rules at museums and attractions vary; check before you go. Airline personal-item sizes vary by airline and fare.

## FAQ

### What size daypack is best for city travel?

About 10–20 liters covers most days out. That holds water, a layer, snacks, and a small camera. Go smaller if you only carry a phone and wallet, larger if you carry a laptop every day.

### Is a sling enough instead of a daypack?

For warm city days with few things, yes. A sling usually can’t fit a rain jacket, a warm layer, and a full water bottle together, so pair it with a packable daypack if your days need more.

### Can my daypack be my personal item?

Yes, if it fits your airline’s personal-item dimensions and slides under the seat. That’s the simplest setup on fares that include a personal item.

### Do packable daypacks hold up?

They are fine for light loads like water, a jacket, and snacks. Thin straps and fabric make them uncomfortable and more prone to wear with heavy items like laptops.


## Related OneBag Kit guides

- [How to choose a carry-on travel backpack (deep guide)](https://onebagkit.com/how-to-choose-a-carry-on-travel-backpack/index.md)
- [What goes in your personal item vs carry-on?](https://onebagkit.com/personal-item-vs-carry-on/index.md)
- [How to pack with only a personal item](https://onebagkit.com/personal-item-only-packing/index.md)
- [Rain jacket or umbrella for travel?](https://onebagkit.com/rain-jacket-or-umbrella-for-travel/index.md)
- [How to measure a carry-on bag (and does squishing work?)](https://onebagkit.com/how-to-measure-a-carry-on-bag/index.md)
- [How to pack carry-on / one bag](https://onebagkit.com/carry-on-one-bag-packing/index.md)

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