1 8

Dog Backpacks

K9 Sport Sack Trainer — Dog Backpack, 4 to 30 lb, Four Sizes

K9 Sport Sack Trainer — Dog Backpack, 4 to 30 lb, Four Sizes

4.569 reviews
$49.95
$49.95
Sale Sold out
Shipping is free. Discounts and any tax are calculated at checkout.
Ships from the U.S.California & Nevada, 1–5 business days Free U.S. shippingOn every order, no minimum Fit guaranteeIf it does not clear the limit we published, we pay the return
Color
Size

The entry-level one, and the maker says so plainly: short, non-strenuous activities — a short walk, the bus, a puppy learning that the world is fine from up there. It is the model for a dog still growing or still getting used to being carried.

The measurement that matters here

A carrier is sized by the bag. A backpack is sized by the dog. Measure along the spine, from the collar to the base of the tail, and buy that size — the weight limit is the second check, not the first. Between two sizes on length, go by weight: this rides on your shoulders and a bag that is too big swings.

  • X-Small — 10–13 in from collar to tail
  • Small — 13–17 in from collar to tail
  • Medium — 17–20 in from collar to tail
  • Large — 20–23 in from collar to tail

Up to 30 lb in every size. No airline takes a dog backpack under the seat with the dog inside it, so none of the numbers on this page are cabin numbers.

What it does well

  • Lumbar support strap on Small, Medium and Large. Not on X-Small — the maker leaves it off that size, and we would rather you knew before you ordered.
  • Ventilated panels and a collar enclosure, same as the bigger models.
  • Fits most comfortably on an owner of small to medium build.

If you are planning long days or hills, the Air 2 is built for that and the Knavigate for more again.

This is a backpack for walking, not a carrier for flying. It is worn, so the space it needs is your back, not the space under a seat. If you are booking a flight, our cabin carriers publish a footprint and a height checked against nine U.S. airlines.

How to measure your pet

Two measurements decide everything.

Length. With your pet lying down, measure from the nose to the base of the tail — not the tip. Add 2 inches. That is the interior length you need.

Height. With your pet standing, measure from the floor to the top of the head.

Your pet must be able to stand up and turn around inside the carrier. That is the rule every airline writes, and the one gate agents actually check. If your pet falls between two interior sizes, take the bigger one — but check its exterior against your airline first. A bag your pet fits in but the airline will not take is no use to either of you.

Shipping & delivery

We ship within the United States only, from warehouses in California and Nevada. Orders placed before 1pm ET on a business day are handed to the carrier the same day; after that, the next business day.

Delivery is typically 1–5 business days depending on how far you are from the warehouse. Shipping is free on every order, with no minimum — you never pay for delivery. Alaska, Hawaii and Puerto Rico are included at the same price; allow a few extra days for those three.

You get a tracking number by email as soon as the label is created.

Returns & exchanges

Thirty days from delivery, in the original packaging and unused. Email us and we will send you a return authorisation and the address for that warehouse before you post anything — a parcel sent back without one cannot be credited.

Wrong size is the most common reason people write to us, and it is the easiest to solve: tell us your pet's measurements and your airline and we will tell you which size to swap to.

View full details
4.56 9 reviews
Why buy it here

The measurements come first

Sized before it is listed

Every carrier lists a length, width and height. Every backpack lists the back length and the weight limit it is built for. The numbers are on the page before you buy, not in the box after it arrives.

Shipped from inside the U.S.

California and Nevada. No customs form, no six-week wait. Most orders leave in a single parcel; where a kit is drawn from two different warehouses we say so on the product page.

Ask before you buy

Send us your pet’s measurements and your airline. We will tell you which size to order, or tell you honestly that we do not have one that fits.