The Secret Indoor Playground Hidden Inside the Art Gallery of NSW
Looking for free things to do with kids in Sydney? This one might be the best-kept secret in the city.
If you haven’t heard about The Key’s Under the Mat yet, you’re about to bookmark this page and thank yourself later. Tucked away on Level -4 of the Art Gallery of NSW, this is one of the most unique free kids activities in Sydney — and honestly, it’s unlike anything else in Sydney!
It’s not just an art installation. It’s an immersive, interactive experience where your family is invited to walk in, explore, touch things, play and make themselves completely at home.
What’s Inside?
This is where it gets really good. Here’s what you’ll find when you walk through the door:
For the kids:
- A unique indoor playground with climbable artwork
- A dedicated water play area
- Swing set showers
- Books for kids to read and explore
- Hidden nooks and spaces to discover
For the whole family:
- Loads of comfortable seating throughout the space
- BBQ facilities
- A little café on-site if you need a coffee or a snack
- A relaxed, welcoming atmosphere that isn’t precious about kids touching things
And yes — there are also two saunas and clothes dryers. The installation leans into the idea of true hospitality — you can wash and dry your clothes if you need to.
Top Tips for Visiting with Kids
- Pack a picnic. There’s space to spread out and eat inside, so you don’t need to spend a cent.
- Bring a change of clothes. The water play area is a hit with little ones, and wet kids are happy kids.
- Combine it with the Royal Botanic Garden. The gardens are right next door and make for a perfect full day out — both completely free.
- Go on a Wednesday evening. The installation is open until 10pm on Wednesdays, which makes it a great option for a family evening out after school or work.
- Don’t rush. Give yourself at least 90 minutes to properly explore everything — there’s more to discover than you’d expect. It’s accessible. The space is welcoming for families with prams and children with different needs.
The Key’s Under The Mat – A free Sydney Activity worth making time for. In a city where family activities can add up fast, finding something this special for free feels like striking gold. The Key’s Under the Mat is one of those experiences that doesn’t feel like a compromise — it’s genuinely worth going out of your way for.
Kids activities in Sydney don’t come much better than this.
Location– Art Gallery of NSW — Naala Badu Building, Lower Level 4 (Nelson Packer Tank)
Hours – Open daily, 10am – 5pm (Wednesday until 10pm)
Cost – Free entry, no booking required
Parking – Domain Car Park nearby on Art Gallery Road
Public Transport – Train to Martin Place or St James, short walk
