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Central Coast Bushwalk

Tunnel Trail (12km) Return

A 12km return walk in Brisbane Water National Park to a hand cut sandstone tunnel under the railway, with a pool alongside. Only walk it at low tide.

At a glance

Distance
12km return
Ascent
150m
Tide
Check the tide before you go
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This is one of my favourite big day walks in Brisbane Water National Park. It follows the Tunnel Fire Trail off Woy Woy Road, drops down to Mullet Creek, and finishes at a hand cut sandstone tunnel that carries the creek right under the Sydney to Newcastle railway line. On a warm, clear day the pool beside it is perfect for a swim, and standing inside the tunnel looking up at the stone arch is quietly astonishing.

The culvert was built in the 1880s to let Mullet Creek pass beneath the main northern railway, and the ridge above it holds the Woy Woy railway tunnel, which at nearly 1.7km was the longest railway tunnel in Australia when it opened in 1888.

It is a proper 12km return, mostly along fire trail with a steep pinch down to the creek and back up again, so bring plenty of water, sturdy shoes and a sense of adventure.

Warning: Only do this walk at low tide. The tunnel fills as the tide comes in, so check the tide times before you set out and leave yourself plenty of room to get back.

Walk directions

  1. Start, head off along the Tunnel Trail: -33.48118,151.29511
  2. Turn right along the Mullet Creek Fire Trail: -33.46066,151.30967
  3. Come off the Mullet Creek Fire Trail and head down the track down the hill, go over the tunnel and come down the blue rope on the other side: -33.48533,151.26687
  4. You have reached the Tunnel. Admire the beautiful sandstone arch, wander through to the far side, and go for a swim if the water is clear enough: -33.48458,151.26586
Sandstone tunnel carrying Mullet Creek under the railway line near Woy Woy
Walking down the fire trail toward Mullet Creek
Inside the sandstone tunnel beneath the railway line
The swimming pool beside the tunnel at Mullet Creek
The Woy Woy railway tunnel portal cut into the ridge

If you have the energy, take the short side trip to see the mouth of the Woy Woy railway tunnel itself, a huge sandstone portal cut straight into the ridge. It is worth the detour. This is a remote walk with no facilities once you leave the road, so carry everything you need, keep an eye on the tide, and let someone know your plan before you go.

Similar Bushwalks

Woy Woy Baths (5km Return)Pearly Ponds (6km)Kariong Brook Falls (4km)
The cover of A Cornucopia of Central Coast Walks: watercolour wildflowers, including a waratah and orchids, on a bright yellow background

The book

The cave walks are in the book

A Cornucopia of Central Coast Walks includes the Megacave Loop and both the short and long walks to Ritcher's Cave, each with a map and numbered directions, alongside over 100 other walks on the Coast.

See the book
The cover of The Bush Wee: a girl with red bunny ears and a starry blue dress peeks out from behind a tree beside a waterfall

A picture book

A picture book for little walkers

The Bush Wee is my read aloud picture book for children aged 2 to 7. A little explorer sets off on a big walk in the Central Coast bush, then realises there is no toilet for miles. Along the way it teaches real bush skills, like which soft leaves make good toilet paper.

See the picture book
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This walk is on Darkinung country. Good Architect acknowledges the Darkinung people as the Traditional Custodians of this land and we pay our respects to Elders, past, present and emerging. Darkinjung Land Council.