The Helensburgh Glow Worm Tunnel is one of the most incredible glow worm sites in all of NSW. The tunnel extends far longer than most people would dare to venture, but you don’t need to go far to experience a dazzling display. Come during the day time and you will see a decent number of glow worms if you walk a little distance into the tunnel, but if you want to see a truly jaw-dropping sight then you need to visit at night.
The blue light from thousands of glow worms can be seen before you even enter the tunnel, creating an otherworldly scene that looks like it’s straight out of a fantasy movie.
There is no sound but that of the croaking frogs and dripping water from the tunnel walls, it could be eerie but the glow worms are so bright that it’s hard to feel anything but awe.
Here’s everything you need to know about visiting the Helensburgh Glow Worm Tunnel.
Do no harm: taking care of the glow worms
Before we delve into the details, I wanted to write a note on caring for the glow worms. The Helensburgh Tunnel was shut for many years after the colony was decimated due to thoughtless behaviour (setting off flares amongst other things). The colony has now bounced back and I am sure everyone wants to keep it that way.
We know that 99% of people would never dream of causing damage to the glow worms, so if you haven’t spent any time at a glow worm colony before, please read the next few lines on etiquette so you don’t inadvertently harm them.
Please don’t shine light on the glow worms, they don’t like it and will turn their lights out. To find a spot to observe them and when moving through the tunnel you can use a torch shone directly at the ground, and then turn it out.
You’ll see much fewer glow worms if you keep a light on. Bringing a torch with red light is even better, although still don’t shine it on the glow worms directly. Keep noise to a minimum and if you’re keen on getting a photo, bring a tripod which will allow you to capture the glow worms without shining a light on them. You can read more about glow worm photography in this post.
What to expect from visiting the Helensburgh Glow Worm Tunnel
A quick note on conditions
The tunnel is left much as it once was. The old railway sleepers are still in place for a couple of hundred metres and this helps with the conditions underfoot.
The tunnel is always damp and muddy, but after heavy rain - as it was on our most recent visit - the tunnel becomes extremely wet and muddy (and can even flood). Many of the sleepers become submerged, though they are still easier to walk on than what lies beyond.
After around 100m into the tunnel the sleepers end and you will begin walking on mud and stones, with water levels that vary from just covering the soles of your shoes, to ankle height and higher if you go further. The stones eventually give way to mud, which is slick. Go carefully here because getting any kind of grip is challenging.
I would recommend wearing wellys or shoes you are happy to get completely filthy, ditto for trousers.
If you visit at night, you don’t need to walk more than a couple of steps into the tunnel, where conditions are good. However, if you visit by day, then you’ll need to walk at least a little way in the mud and water, or you won’t see more than a few dozen glow worms.
The Helensburgh Glow Worm Tunnel Walk
It’s a mere 100m from the parking area to the tunnel entrance (you can’t even call it a walk really!). The first 50m are on a little dirt path which goes up and down a small slope. Alternatively you could walk on the sleepers.
For the next 50m to the tunnel entrance, everyone needs to either walk on the sleepers, or to the side of them, depending on which is less wet and muddy at the time!
It’s an easy path, but even this first 100m isn’t somewhere you want to be wearing nice shoes unless it’s been very dry.
Even before you reach the inside of the tunnel the scenery is fantastic. It’s very atmospheric with the railway line running between the fern covered cliff walls - the foliage has even begun creeping down to the tunnel entry way, which gives it a wild vibe. The old train station signpost is still there and it feels mysterious, even if you visit during the day.
The internet tells me the tunnel itself extends for 624m, but I confess, due to conditions I couldn’t go the whole way. I actually think you’d need waders and a bit of a bravery for that!
We’ll go into how far you need to go to see the glow worms in the next section, as it varies by day and by night.
The Helensburgh Glow Worm Tunnel by day
The wonderful thing about viewing glow worms in caves and tunnels is that you can visit by day. The less wonderful thing about visiting the Helensburgh Tunnel by day is that a lot of light passes through the tunnel entrance, which means you have to go a fair distance to see many glow worms.
If you only walk a little way by day, you will probably think the tunnel is pretty cool, but it’s unlikely that you’ll be wowed.
I walked for 220m into the tunnel (plus the 100m to the tunnel entrance) and this allowed me to see quite a few hundred glow worms. If you only want to walk to the sleepers or along the mud before you hit the deeper water, you will still see glow worms, but in lower numbers.
Think a few dozen rather than hundreds. And even for this you need to make sure you turn your torch off and let your eyes adjust. Anytime someone turns a torch on you’ll need to allow a little more time for your eyes to adjust again.
The first alcove we saw on entering the tunnel appeared to have around five glow worms, approximately ten minutes later we could see four times that amount. If you think about the numbers on the ceiling (where the majority of glow worms are) then you can see how much of a difference it makes.
If you are confident walking further into the tunnel, which becomes very slippery after 150m or so, then it gets better and better. I never walked beyond where I could still see some light from the opening, so I never saw just how good it could be, but as mentioned the conditions further into the tunnel are not ideal!
By the point I turned back, I’d already got really wet and dirty, so it wasn’t the slippery mud that turned me around. In the end it was so slick and squelchy, I thought I’d go right over and that was something I wasn’t ready for : )
The Helensburgh Glow Worm Tunnel by night
If you can, I would strongly recommend visiting the tunnel by night. The glow worms begin on the cliff walls even before you reach the tunnel entrance.
Standing in front of the tunnel (even several metres back) you’ll see an otherworldly blue light beam out of the entrance and I defy anyone to stand in front of it and not be completely wowed.
I think my jaw may actually have dropped. We’ve visited over 60 glow worms sites and this one is something special.
If you’re not keen on the idea of the water and mud further into the tunnel, know that at night you can walk for two steps into entry and see thousands of glow worms. Even at night you still need to let your eyes adjust, but you definitely don’t need to walk far.
The ceiling is covered in one of the densest glow worm displays I have ever seen.
Walking further into the tunnel is better still, but honestly, not massively so like it is in the day time, you just get to feel more immersed.
Even though it’s a tunnel environment and therefore a better viewing experience than a bush environment, it’s still better to come at least 30 minutes after sunset and the later the better.
The tunnel entrance still allows a decent amount of light in, so you do want it to be properly dark for maximum effect.
Getting to the Helensburgh Glow Worm Tunnel
The Helensburgh Glow Worm Tunnel is located in the suburb of Helensburgh, about 65km and a one hour drive from Sydney and 37km and 35 minutes from Wollongong.
You can find the entrance here on Google maps. There is room for several cars to pull fully off the road and room for cars to park on the residential street. And on that note, it is a residential street, so please visit respectfully and keep noise to a minimum.
You could also walk to the tunnel from the new Helensburgh Train Station, which takes about 5 - 10 minutes and is a distance of 450m.
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