Boys' Halloween costumes tend to succeed or fail on one thing: how easy they are to move in. A costume that restricts running, climbing, or sitting down rarely lasts the whole night.
Start with what they already do
If your child spends the evening running, avoid long capes that drag and trousers that need holding up. Hooded costumes, jumpsuits, and tunic-style tops give the same effect with far more freedom.
Costume directions that always land
Skeletons, pirates, superheroes, ninjas, dinosaurs, and vampires stay popular because they are recognisable from a distance and come in shapes that fit like ordinary clothes.
Skip the full mask
Masks fog up, slip, and block peripheral vision on dark pavements. A hood, hat, or a little face paint gives you the character without the complaints.
Layer underneath
Most costumes are a single thin layer. A long-sleeved top and leggings underneath keep the evening comfortable, so buy with room for that extra layer.
Choose props carefully
One prop is great, three get dropped. Soft, lightweight props are best, and anything that must be carried should fit in a pocket or on a belt.
Check it survives the wash
Costumes meet mud, sweets, and pavement. A machine-washable costume can be worn again next year or added to the dress-up box.