Glow worms are supposedly unique to New Zealand but I read somewhere there are a few caves in Australia that have them. Regardless, they are not to be missed and are really cool to see. Glow worms attach themselves to the ceiling of caves or under over-hangings and let down a thin thread that emits a bioluminescent light that attracts its prey. They tend to be found in large colonies.
The most popular of the glow worm caves in New Zealand is in Waitomo. Waitomo has several caves you can visit but not all of them have glow worms. An adult ticket is $49 and the tour lasts about an hour so it isn’t cheap but it’s a great experience. Check out the options for seeing more than one cave as they are really different from each other and well worth it. In the glow worm cave, the tour starts you out with a walk through the cave that focuses mostly on how the caves were formed and the formations inside. There’s a brief stop to see glow worms underneath a rock hanging during this part.
But then they end the tour with a boat ride through a section of the cave — in the ride, they turn off all of the lights and the guide pulls the boat through the water on a rope. They ask you to be quiet and you put your head back and stare at the roof of the cave with beautiful shiny pinpoints of light like stars in the sky. Except more stars than you can imagine! The boat ride only lasts about 10 minutes but it is really cool.
Waitomo is a guaranteed place to see glow worms but if you keep your eye out you can see them in other places. We went tubing in a river in the South Island last Christmas — the water was crazy cold even in the summertime but we had wet suits on and at one point the guides had the tubers connect up in a row and pulled us through a tunnel in the caves where the roof of the tunnel is full of glow worms. It’s even better than Waitomo becuase you’re in the water and it’s a more personal experience. Once you get inside, we had a quick pit stop for some hot chocolate and a chocolate bar before connecting back up and exiting.
If you know what to look for, you can see glow worms in the forest as well. We stayed at the Stagecoach Hotel in Otira last summer (I highly recommend it). After dinner, the hotel owners offered us a quick visit to see the glow worms and we took them up on it. A short trek down the road and through the bush and 15 minutes later we were standing in the woods with our flashlights off oohing and aahing.