Natural Tunnel

What it is

A short, naturally carved rock passage on the famed Crypt Lake Trail, the Natural Tunnel is just under 100 feet long. You can’t stand upright inside, so expect to stoop or briefly crawl. It comes right after an exposed ladder climb and before a cable-assisted traverse, making this section the hike’s most talked‑about sequence.

Why it’s worth your time

Most trails don’t make you thread a cliff via a naturally eroded tunnel—this one does. It’s a fun, memorable obstacle that punctuates a route already packed with scenery: waterfalls on the approach and big, dramatic views toward Crypt Valley beyond the tunnel.

Getting there

Access is by boat shuttle across Upper Waterton Lake to Crypt Landing; from there, you hike to the tunnel along the Crypt Lake Trail. There are no facilities at the tunnel itself—this is pure backcountry.

What to expect inside

It’s dark, tight, and can be damp or muddy. You’ll likely pass packs through first and shuffle along bent over. The tunnel pops you onto airy terrain where a fixed steel cable helps with the ledge traverse.

Wildlife

Higher elevations on this route often host mountain goats and bighorn sheep. Bears are present in the area—carry bear spray and know how to use it.

Safety notes

Move slowly; the rock can be slick. The exposed ledge after the tunnel is manageable for most prepared hikers but intimidating for some. Weather changes fast at elevation—avoid the exposed sections in thunderstorms or heavy rain.

Best time to visit

• Midweek mornings are best: catch the earliest ferry to beat the rush and avoid the tunnel bottleneck.
• Photographers: the tunnel interior is dim regardless; bring a light. Views just beyond the tunnel are nicest with midday–afternoon light on the valley walls.
• Peak summer weekends see crowds at the tunnel and on the ferry; plan extra time.

Practicalities

There are no amenities at the tunnel or along the mid-trail stretch: no toilets, water taps, or shelters. Bring a headlamp or flashlight, sturdy boots, gloves for the cable section, layers, plenty of water and food, and your ferry ticket. Missing the last boat makes for a long wait and a logistical headache.