Quick answer: A DIY cat tunnel system is three to five sturdy boxes joined into a route with two openings at each end. Children measure, decorate and test; adults cut and join. Use boxes at least 30 cm across, join them with paper tape or cotton ties rather than staples, and finish in one or two colours so it suits the room.
A tunnel system is a perfect weekend project for children because every step is visible and the cat tests the result straight away. Unlike a single tunnel, a system has junctions, a lookout and more than one way out, which gives the cat choices.
This plan splits the work across Saturday and Sunday, gives each age group a real job, and keeps the finished piece looking like it belongs in a designed living room rather than a recycling pile.
What Makes a Good DIY Cat Tunnel System
International Cat Care notes that during play, boxes or tunnels can be used to pull a toy through or around, which keeps the game interesting. A system multiplies that: the cat can dash in one end, pause at a junction and pop out somewhere else.
Three features matter most. Every section should be wide enough for the cat to turn around. There should be at least two exits so the cat never feels trapped. And the whole thing should sit flat and stay put when the cat charges through it.
Matching Tasks to Each Child's Age
| Age | Good jobs | Adult-only |
|---|---|---|
| 3–5 | Choosing colours, sticking paper shapes, testing with a wand toy | Anything with blades |
| 6–9 | Measuring with a tape, marking cut lines, wrapping joins with paper tape | Cutting openings |
| 10–13 | Planning the layout on paper, cutting with safety scissors, threading cotton ties | Craft knife work |
| Adults | Cutting, final checks, removing staples and plastic tape | All of these |
Children enjoy the project more when their job affects the result. Let them choose the route on paper before anything is cut.
Materials for a Five-Box System
| Item | Amount | Why |
|---|---|---|
| Strong boxes, at least 30 x 30 cm cross-section | Five | Room for an adult cat to turn |
| Paper tape (gummed or water-activated) | One roll | No plastic tape for the cat to chew |
| Cotton tape or cord | About 3 m | Ties sections together and can be undone |
| Plain fabric remnant, such as canvas | About 1 m | Covers the top for a tidy look |
| Washable mat | One | Stops the system sliding on hard floors |
| Craft knife and cutting mat | Adult use only | Clean openings |
Our guide to tape, ink and staples to avoid in cardboard projects explains why plastic tape and staples come out before the cat goes in.
Saturday Morning: Plan and Prepare
- Pull every staple and strip of plastic tape from the boxes. This is an adult job.
- Children measure each box and write the sizes on a sheet.
- Together, draw the route: a straight run, one junction and a lookout box at the end.
- Mark where each opening goes. Openings should be about 15 to 18 cm across, roughly a cat's shoulder width plus room to spare.
- Agree on one or two colours for the finish.
Planning first prevents the most common problem: a tunnel that looks fun but has a dead end in the middle.
Saturday Afternoon: Cut and Join
An adult cuts the openings with a craft knife on a cutting mat while children hold the box steady from the far side. Round the corners of every opening so there are no sharp points at face height.
Join the boxes end to end with paper tape on the outside, then punch two small holes on each side of the join and tie the sections with cotton cord. Ties make the system modular: you can undo them later and rearrange the route.
Sunday: The Design-Forward Finish
A tunnel that suits the room is more likely to stay out. Cover the tops with a single fabric remnant held by cotton ties, or paint the outside with a water-based paint and let it dry fully, outdoors if possible, before the cat uses it. Keep the inside plain cardboard.
Neutral colours, one accent, and clean openings make a cardboard system look intentional. If you want more ideas for a finished look, our design-forward cardboard castle uses the same approach on a larger build.
Sunday Afternoon: Introducing the Cat
Put the system against a wall where the cat already likes to play, with the exits facing open floor. Children can drag a wand toy slowly past one entrance and let the cat follow it through. International Cat Care also notes that play sessions with kittens may only last a few minutes, so keep the first test short.
Ohio State's Indoor Pet Initiative suggests rotating toys a few at a time to keep them interesting. Apply the same idea: leave the system out for a week, then rearrange the boxes so the route feels new. Our cardboard rotation system has a schedule for that.
Safety Checks Children Can Help With
- Run a hand around every opening to feel for sharp edges or loose tape.
- Push gently on each box; the system should not slide or collapse.
- Look inside with a torch for staples, string or small paper pieces.
- Keep wand toys out of the tunnel when no adult is watching, since string is a swallowing risk.
- Retire any box that gets wet or soiled.
VCA Animal Hospitals warns that cats easily swallow thread, string and yarn, which can cause serious internal injury. Make wand toys a supervised-only item and keep them in a closed box afterwards.
Adapting the Design for Different Cats
A confident young cat will race through a long straight run, so add a junction halfway with a side opening it can burst out of. A shy cat prefers a shorter route with a covered lookout box at one end where it can sit and watch the room unseen.
For a large or long-bodied cat, use bigger boxes rather than wider openings, since the openings still need firm edges to keep the box rigid. For a kitten, start with two boxes and add more as it grows in confidence. Older cats often like a single low box with a soft folded towel inside more than a full system.
Keeping It Going After the Weekend
Cardboard wears out. Check the system each weekend with the children: squash test each box, look at the openings and replace any section that has gone soft or been chewed. Because the joins are cord ties, swapping one box takes a few minutes and the children can do most of it.
Keep a spare box or two flat in a cupboard. When one section fails, the system stays in use instead of disappearing for a week while you find another box. Our apartment version of the kids-and-cats castle weekend has more uses for the spares.
Write the date on the inside flap of each new box with a pencil. After a month or two you will know how long sections last in your home, and children can keep track of which one is due for replacement next.
Where to Place It in a Family Home
Keep the system out of the busiest path so children do not trip over it and the cat can use it calmly. Along the back of a sofa or under a window works well. Avoid placing an exit right beside the sofa corner if your cat scratches there; point it towards a scratcher instead.
Our cardboard castle weekend with kids and the under-an-hour moving box castle with kids offer two more family builds once the tunnel is done, and the cardboard safety checklist covers what to inspect each week.
Kids-and-Cats Tunnel Questions
How big should a DIY cat tunnel be?
Each section should be at least 30 cm across so an adult cat can turn around, with openings about 15 to 18 cm wide. A system of three to five boxes, with two exits at each end and one junction or lookout, gives enough choice without filling the whole room.
What can kids safely do when building a cat tunnel?
Young children can choose colours, stick paper shapes and test the tunnel with a toy. Children from about six can measure, mark lines and wrap joins with paper tape. Older children can plan the layout and thread cotton ties. Adults should do all craft knife cutting and remove staples.
What should I use to join cardboard tunnels?
Paper tape on the outside, plus cotton cord through small holes either side of each join. Avoid staples and plastic packing tape, which cats can chew or catch on. Cord ties also let you undo the sections and rearrange the route, which keeps the system interesting for longer.
How do I get my cat to use the tunnel system?
Place it where your cat already plays, with exits facing open floor, and slowly drag a wand toy past an entrance so the cat follows it through. Keep the first session short. Rearranging the boxes every week or so makes the route feel new and keeps the cat exploring.
