Small dogs
Securing a small dog or puppy in the car
Last updated: 2026-09-22
Small dogs and puppies must be restrained just like large dogs — Rule 57 applies to every size. Use a snug small-dog harness and a seat belt restraint set short so they can't slip free or reach the footwell. Our belt adjusts down to 45cm; never clip to a collar.
The quickest way to keep your dog restrained and legal is an adjustable 3-in-1 dog car seat belt that clips into any standard seatbelt socket.
Small dogs still need restraining
A small dog loose in the car is still a distraction and is still thrown forward in a crash — and being light doesn't make it safe. A dog on your lap is especially dangerous and can lead to a careless-driving penalty.
The right harness and strap length
Choose a small-breed harness that fits snugly without slipping over the head, and keep the restraint short so your small dog stays on the seat and can't wriggle into the footwell. Our seat belt shortens to 45cm, which suits toy and small breeds like a Chihuahua, Frenchie or a small terrier.
A note on puppies
Only use a car harness once your puppy is big enough to wear one that fits properly; for very young puppies a secured, crash-tested crate or carrier is safer. Introduce the car gradually with short trips, and watch for car sickness, which is common in puppies.
Frequently asked questions
At what age can a puppy use a car seat belt?
Once the puppy is big enough to wear a properly fitting harness. For very young puppies, use a secured crate or carrier instead, and build up car time with short trips.
Can my small dog just sit on my lap?
No. A dog on your lap is a serious distraction, unsafe in a crash, and can lead to a careless-driving penalty. Restrain them on a seat.
Will one seat belt fit a very small dog?
Yes — our restraint adjusts down to 45cm. Pair it with a correctly sized small-breed harness for a secure fit.
Sources: UK Highway Code, Rule 57. Guidance only — not veterinary or legal advice.