5 Best Cat Flaps for Glass Doors (2026)
From the Pet Doors Ontime Advice Centre
One of the most common questions we’re asked is:
“What’s the best cat flap for my glass door?”
The honest answer is that there isn’t one perfect cat flap for every home.
After installing cat flaps into glass doors for homeowners across Australia, we’ve learnt that the right choice depends on your cat, your glass, your door type and where the cat flap will be installed.
A cat flap that looks beautiful in a sheltered alfresco area may not be the best choice for a door that faces wind and rain. A microchip cat flap might be perfect for keeping neighbourhood cats out, but it may not suit many sliding glass doors because of clearance issues.
That’s why we always recommend choosing the cat flap before replacement glass is ordered.
In this guide, we compare five popular cat flaps for glass doors:
- Hakuna Super Tough Cat Flap
- Pet Tek Catwalk Cat Door
- Transcat Cat Door
- Premium Underbelly Cat Flap
- SureFlap Microchip Cat Flap
We’ll explain where each one performs best, what to watch out for, and what we’d recommend if it were our own home.
At a Glance
Reading time: 7 minutes
Best for: Homeowners comparing cat flaps for glass doors
Written by: The Pet Doors Ontime Team
In this guide, you’ll learn:
- Which cat flaps suit glass doors
- Which models work best in sliding doors
- Which cat flaps have weather seals
- Which options look the most discreet
- When a microchip cat flap is worth the extra cost
Why Choosing the Right Cat Flap Matters
A cat flap in glass is not like a cat flap in timber. And not all cat flaps can be installed into glass.
With timber, a hole can usually be cut on site. With glass, it’s different. Most modern glass doors are made from toughened safety glass, which cannot be cut after manufacture.
In most cases, the existing panel needs to be replaced with a new piece of Grade A Toughened Safety Glass manufactured with the cat flap opening already cut.
That means the cat flap you choose affects:
- The size of the glass cut-out
- Whether the panel can be manufactured safely
- How the finished door will look
- Whether the door still slides properly
- How well the cat flap handles weather
- How secure the installation feels
Buying the cheapest cat flap online can end up costing more if it does not suit your glass or needs to be replaced later.
🐾 Pet Doors Ontime Pro Tip:
Before buying any cat flap, check your glass panel size and door clearance. The best cat flap is the one that suits the installation—not just the one that looks good in the box.
Comparison: Best Cat Flaps for Glass Doors
| Cat Flap | Locking | Weather Seal | Aesthetics | Sliding Door Suitable | Best For |
|---|---|---|---|---|---|
| Hakuna Super Tough Cat Flap | 2-way locking | Yes – excellent weather seal | Robust design, available in black and white | Good | Exposed locations and busy homes |
| Pet Tek Catwalk Cat Door | Manual locking | Good weather protection | Practical, neat appearance | Good | Everyday cat access |
| Transcat Cat Door | 4-way locking | No weather seal | Slim, discreet and low profile | Excellent | Sheltered glass doors |
| Premium Underbelly Cat Flap | 4-way locking with optional Secure Lock Cover | No weather seal | Premium minimalist look, hardly visible in the door | Excellent | Modern homes where appearance matters |
| SureFlap Microchip Cat Flap | Microchip controlled | Good weather protection | Larger frame due to electronics | Often not suitable | Homes needing selective cat access |
1. Hakuna Super Tough Cat Flap
The Hakuna Super Tough Cat Flap is built for durability. It has a more robust appearance than some of the slimmer options, but that is also part of its appeal.
Where this cat flap really stands out is weather protection. It includes an integrated weather seal, making it a strong option for doors that are more exposed to wind or rain.
It is available in a black or white frame, which gives homeowners some flexibility depending on the colour of their door frame or interior.
Why we like it
The Hakuna Super Tough is a practical choice when performance matters more than a barely-there look. If the door is used often, or the location is exposed, this is one of the more sensible options.
Things to consider
It has a more noticeable frame than the Underbelly or Transcat. It also has a 2-way locking mechanism rather than 4-way locking.
Best suited for
- Exposed rear doors
- Busy households
- Homes where weather sealing matters
- Owners who want a stronger, more durable cat flap
🐾 Pet Doors Ontime Pro Tip:
If your glass door faces wind or rain, choose a cat flap with a weather seal. Minimalist cat flaps can look fantastic, but they are not always the best option for exposed locations.
2. Pet Tek Catwalk Cat Door
The Pet Tek Catwalk Cat Door is a reliable everyday option for homeowners who want a practical cat flap that performs well without overcomplicating things.
It has a neat appearance, good usability and is commonly used for cats and small pets.
Why we like it
Pet Tek products are popular because they offer dependable performance and suit a wide range of residential installations.
The Catwalk is a good middle-ground option. It is not as discreet as the Underbelly or Transcat, but it offers more practical weather protection than non-sealed minimalist models.
Things to consider
It is more visible in the glass than the Premium Underbelly or Transcat. If your main priority is a premium architectural finish, there are more discreet options.
Best suited for
- Everyday cat access
- Homes needing a practical all-rounder
- Sliding or fixed glass panels (although is slightly bulkier than the Transcat design)
- Customers wanting a balance of price, durability and performance
3. Transcat Cat Door
The Transcat Cat Door has been a favourite among Australian glaziers for many years.
It is simple, reliable and has a slim profile that looks neat in glass. For many homeowners, especially those with a sheltered patio or alfresco area, the Transcat is a very practical choice.
Why we like it
The Transcat is discreet, easy for cats to use and gives homeowners reliable 4-way locking without batteries or electronics.
It is one of the better-looking manual cat flaps for glass doors.
Things to consider
The Transcat does not include a weather seal, so we would not usually recommend it for doors directly exposed to heavy rain or strong wind.
Best suited for
- Sheltered glass doors
- Covered alfresco areas
- Standard-sized cats
- Homeowners wanting a slim, low-profile cat flap
🐾 Pet Doors Ontime Pro Tip:
The Transcat is a great choice when appearance and simplicity matter. Just make sure the installation location is protected from direct weather.
4. Premium Underbelly Cat Flap
If appearance is your top priority, the Premium Underbelly Cat Flap is one of the best-looking options available.
Once installed, it is hardly visible in the glass compared with many traditional plastic-framed cat flaps. For modern homes, renovated living areas and large glass doors, that makes a big difference.
It also has an optional Secure Lock Cover, which gives homeowners an added layer of security when they want the opening fully covered (like when you go on holidays and you want that extra security)
Why we like it
The Underbelly is one of the most discreet cat flaps we recommend. It has a premium, minimalist finish and works especially well in modern glass doors where a bulky frame would stand out.
If this were our own home and the door was under cover, the Underbelly would be one of our first choices.
Things to consider
The Underbelly does not have a weather seal. It is best suited to protected or undercover locations rather than doors exposed directly to driving rain.
Best suited for
- Modern homes
- Sliding glass doors
- Covered alfresco areas
- Homeowners who care about aesthetics
- Larger cats needing a generous opening
🐾 Pet Doors Ontime Pro Tip:
The Underbelly looks fantastic in glass, but location matters. We usually recommend it for sheltered doors where its minimalist design can shine without needing heavy weather protection.
5. SureFlap Microchip Cat Flap
The SureFlap Microchip Cat Flap is the best option in this list for selective access.
Instead of allowing any cat to come through, it reads your cat’s existing microchip and only opens for approved pets. This makes it useful for households dealing with stray cats, neighbourhood cats or food theft.
Why we like it
When security is the priority, microchip cat flaps are hard to beat. They are especially useful if your cat’s food, litter tray or sleeping area is close to the door.
Things to consider
Microchip cat flaps are significantly more expensive than manual options. They also require batteries and occasional maintenance.
The biggest issue we see with glass installations is clearance. The SureFlap has a deeper internal housing than most manual cat flaps, which means it is often not suitable for many sliding glass doors.
Best suited for
- Homes with unwanted neighbourhood cats
- Single or multi-cat households needing access control
- Fixed glass panels or hinged doors with enough clearance
- Owners happy to pay more for security
🐾 Pet Doors Ontime Pro Tip:
Before choosing a microchip cat flap for a sliding door, always check clearance. This is one of the most common reasons a microchip model may not be suitable.
Which Cat Flap Looks Best in Glass?
For appearance, our top picks are:
Premium Underbelly Cat Flap
Transcat Cat Door
Pet Tek Catwalk Cat Door
Hakuna Super Tough Cat Flap
SureFlap Microchip Cat Flap
The Premium Underbelly and Transcat are the most discreet options. They suit homeowners who want the cat flap to blend into the glass rather than stand out.
The Hakuna and Pet Tek are more visible, but they offer stronger practical benefits in the right location.
The SureFlap is the most noticeable due to its electronic components, but that is the trade-off for microchip selective access.
Which Cat Flap Is Best for Weather?
| Cat Flap | Weather Suitability |
|---|---|
| Hakuna Super Tough | Best for exposed locations |
| Pet Tek Catwalk | Good everyday weather protection |
| SureFlap Microchip | Good weather protection |
| Transcat | Best for sheltered locations |
| Premium Underbelly | Best for sheltered locations |
If the cat flap will be installed in a protected area, the Underbelly or Transcat are excellent choices.
If the door is exposed to wind and rain, the Hakuna Super Tough or Pet Tek Catwalk will usually be more suitable.
Which Cat Flap Is Best for Sliding Glass Doors?
For sliding glass doors, slim manual cat flaps are usually the safest choice.
Our preferred options are:
Premium Underbelly Cat Flap
Transcat Cat Door
Pet Tek Catwalk Cat Door
Hakuna Super Tough Cat Flap
We are more cautious with microchip cat flaps in sliding doors because the larger housing can interfere with door clearance.
This does not mean a microchip cat flap is never possible. It means the door needs to be checked carefully before glass is ordered. And you may need a glass fitting adaptor.
Five Mistakes We See Every Week
After installing cat flaps into glass doors for years, we see the same mistakes again and again.
1. Buying the cat flap before measuring the glass
This is the big one. The cat flap might suit your cat but not your glass panel. Not all pet doors are suitable for glass.
2. Ignoring sliding door clearance
Some cat flaps are too deep for sliding doors. This is especially common with microchip models.
3. Choosing style over weather protection
A minimalist cat flap may look beautiful, but it may not suit a door exposed to rain.
4. Choosing a flap that is too small
Cats are flexible, but they still need comfortable clearance. Larger breeds may need a bigger opening.
5. Assuming existing toughened glass can be cut
In most cases, it cannot. A new glass panel usually needs to be manufactured with the correct opening.
Our Recommendation
If this were our own home, this is how we would choose.
Best overall appearance: Premium Underbelly Cat Flap
Best value: Transcat Cat Door
Best for exposed locations: Hakuna Super Tough Cat Flap
Best all-rounder: Pet Tek Catwalk Cat Door
Best security: SureFlap Microchip Cat Flap
For a modern home with a sheltered sliding glass door, we would lean towards the Premium Underbelly Cat Flap.
For a protected patio or alfresco area, the Transcat Cat Door is a simple and reliable choice.
For a door exposed to weather, we would usually recommend the Hakuna Super Tough or Pet Tek Catwalk.
For unwanted neighbourhood cats, the SureFlap Microchip Cat Flap is worth considering, provided your door has enough clearance.
Frequently Asked Questions
Need Help Choosing?
Not every cat flap suits every glass door.
If you are unsure which option is right for your home, send Pet Doors Ontime a photo of your door. We can help you work out:
- Which cat flaps are suitable
- Whether your glass needs replacing
- Whether your sliding door has enough clearance
- Which option we would recommend
Getting the right advice before ordering can save time, money and frustration.
Try our online calculator for an instant quote or give us a call on 1300 940 801 for more advice.
