Both MiaMily sizes share the patented seat, the child belt, the bag hook, the TSA lock and the 360° wheels. The choice is about litres, airline rules, and who is riding.
The numbers
- Carry On: 51 × 38 × 29 cm including wheels, 43 litres, 4.3 kg. Designed to fit most overhead compartments.
- Check In: 66 × 45 × 31 cm including wheels, 77 litres, 6.5 kg. Checked luggage.
The Check In holds about 1.8 times the Carry On. Empty, it weighs 2.2 kg more, which you will feel lifting it into a boot but not while pulling it.
Choose the Carry On when
- The trip is a weekend to a week and you can pack light.
- You want to avoid bag drop and the carousel entirely.
- One child rides, and you want the case with you in the terminal from door to gate.
- Colour choice matters: the Carry On comes in seven colours.
Choose the Check In when
- Overseas or a week or more, with bulky items.
- You are packing for more than one child in one case.
- The child riding is bigger; the wider base adds stability.
- You already have a cabin bag and want the ride-on to be the checked one. The seat still works kerb to bag drop, and carousel to car.
What about the Plus?
Carry On Plus and Check In Plus keep the same litres as their originals and change how you pack: a top-opening lid, one deep space, a quick-access front pocket, a waterproof pocket and a wheel brake. Pick Plus if you travel often and hotel rooms are small; pick the original if you like a clamshell with compartments and want the most colours.
A note on airlines
Cabin allowances differ between Australian domestic carriers and international ones, and the weight limit is frequently the tighter rule. MiaMily describes the Carry On as fitting most overhead compartments; treat that as a design intent and confirm with your airline.
Buy the size for the trip you take most, not the trip you take once.
Related: the size explorer, and the full comparison table.
