Thunder Arm Beach Trail

The Thunder Arm Beach Trail at North Cascades National Park near Diablo, Washington is an easy 0.1-mile one-way walk that leads to the turquoise waters of Diablo Lake / Thunder Arm.

Explore Thunder Arm Beach

Whether you just wrapped up a hike along the Thunder Knob Trail or are simply looking for a scenic and somewhat-secluded view of Diablo Lake, Thunder Arm Beach is well-worth a visit when exploring North Cascades National Park. This short trail begins in the Colonial Creek North Campground and leads visitors out to the southern shore of Diablo Lake. Here, you'll find stunning scenery of the lake's turquoise waters and towering alpine peaks that surround it. Upon visiting Thunder Arm Beach, you may find paddleboarders cruising around the water or kayakers paddling from point to point. While this is a super-short path and really not a hike at all, it's a great way to wind down with the stunning scenery of Diablo Lake.

Camping

Note that this trail does not allow camping or backpacking on it, however, the trail does start at the Colonial Creek North Campground at the park. If you plan to camp at North Cascades National Park, consider this campground. Please follow all rules and regulations when camping and acquire a reservation. See the park's official website for more details.

Restrooms

As of June 2025, this trail has restrooms near the trailhead and parking, which are pit toilets. There are flush toilets in the middle of the Colonial Creek North Campground.

Parking & Fees

Hikers will find a medium-sized parking lot at the coordinates provided, located on the north side of the North Cascades Highway. Do not enter the campground unless you have a reservation, as there are no public parking spaces there. As of June 2025, there are no fees to enter North Cascades National Park, making it one of the few national parks that does not require an entrance fee.

Pets

Dogs are allowed only if leashed and must be cleaned up after.