How to Visit Sandiaoling Tunnel

Sandiaoling Eco-Friendly Tunnel (aka The Dark Line) is a relatively new tourist attraction in New Taipei’s Ruifang District. Previously the tunnel was used by trains heading between Sandiaoling and Mudan, it lay abandoned for almost four decades after being superseded by a newer, wider tunnel, but was reopened as a biking and walking route in 2024. Personally, I think a visit to the tunnel with stops at Houtong Cat Village, Coffee in Mudan Old Street and a bike ride to Shuangxi for drinks or snacks one of the best day trips you can do in New Taipei

It’s free to visit, but a daily cap on visitor numbers (to avoid disturbing the resident bats) means that you are required to apply for permission to enter at a designated time. Fortunately, this process is super simple and takes less than five minutes to complete.

How to apply to visit Sandiaoling Tunnel?

If you’re planning to visit the tunnel, just follow the steps below to make sure you have your entry permit sorted.

Do I need a ticket to visit Sandiaoling Tunnel?

No ticket is required, but you do need to apply to visit in a particular time slot.

How can I get to Sandiaoling Tunnel?

The tunnel is best accessed by train. Depending on your desired direction of travel, you can alight at either Houtong or Mudan. Do not get off at Sandiaoling — there’s no legal way to get across the tracks from Sandiaoling station to the tunnel.

Can I walk through Sandiaoling Tunnel?

Yes, you can walk through the tunnel — in fact, most people walk.

Can I cycle through Sandiaoling Tunnel?

Yes, you can cycle through the tunnel, but I would suggest walking instead. I’ve ridden and walked and I found myself wanting to stop too many times when I was on a bike.

Is it safe for a solo traveller to visit Sandiaoling Tunnel?

Yes, it’s absolutely safe to visit this alone. The whole tunnel has lighting and there are guards at each end, as well as a couple in the middle somewhere. It’s also busy enough with other walkers that you’ll never be on your own for long.

Do I need to take a torch to Sandiaoling Tunnel?

No, the tunnel is well-lit.

How long does it take to visit Sandiaoling Tunnel?

Cycling from Houtong to Mudan takes around an hour and walking takes more like 90 minutes to two hours.

What can I combine with a visit to Sandiaoling Tunnel?

One end of the tunnel is close to Houtong Cat Village and Sandiaoling Waterfall Trail. The other end is within walking distance of the small railway village of Mudan and within cycling distance of the larger railway and riverside town of Shuangxi. My personal recommendation would be to spend a little time exploring Houtong, then cycle or walk through the tunnel, maybe grab a drink in Mudan and head on to Shuangxi for some shaved ice or other energy-restoring treats.

Step 1

Head to the tunnel’s website and toggle to English using the globe icon at the top right. On the first page, read through all of the terms and conditions, then scroll down to the bottom, check the box to agree that you’ve read them and proceed to the next page.

Step 2

Scroll through a second page of reminders and notes and check that you have read it. This one is slightly more important from a logistical perspective — specifically, it points out that your reservation will be invalid if you don’t arrive at the time slot you selected.

Pro tip: You can apply to visit the tunnel on the same day that you visit, and (as long as you don’t visit on a weekend or national holiday), applying while en-route is a sure-fire way to make sure you don’t miss your time slot.

Step 3

Once you’ve waded through the terms and conditions, it’s time to choose your date. You can apply for entry as early as 14 days in advance of your visit and as late as an hour or two before you arrive.

Note: The tunnel is closed on Mondays.

Step 4

Choose the time slot that you wish to make. (It’s worth checking the train times to figure out how long it’ll take you to arrive at Houtong and then how long you’ll need to walk/cycle from there to the tunnel.)

Step 5

You’ll be shown a list of all the other applications for the same date and time slot. Assuming you’re still OK with the date and time you’ve chosen, select “Apply for Admission”.

Step 6

Complete the information asked for in the form. The form demands a mobile number, but I put my parents’ UK landline in and it still worked. The important part here is the email, since this will be used to send confirmation of your application. Although, strictly speaking, even that isn’t necessary because…

Step 7

…as soon as you hit “Submit Application”, it’ll take you to this screen and ask you to save the QR code to your photos so that the tunnel staff can scan it on the date of your visit.