The trailhead is the Grotto Shuttle stop in the main Zion canyon. During spring, summer, and fall months, the Zion shuttle is the only way to access the trailhead. If the shutte isn't running, it is not a good time to be doing Behunin!

Approach (2-2.5 hours):

From the trailhead cross the bridge over the Virgin River, and turn right toward the signed Scout Lookout/Angels Landing. The trail begins climbing and makes a few switchbacks before entering Refrigerator Canyon. This is a great respite from the heat in the summer.

A few minute up Refrigerator Canyon, the trail begins climbing again up the right side, soon entering Walter's Wiggles. This is a unique section of 21 switchbacks. Zig-Zag up them, reaching Scout Lookout. There is a toilet available at Scout Lookout, but no water.

Go left, toward the signed West Rim.

Side Trip: It is an hour or less round trip to visit Angels Landing to the right, and recommended if you have time but now requires a permit in advance. (https://www.nps.gov/zion/planyourvisit/angels-landing-hiking-permits.htm)

Follow the West Rim trail as it follows the rim, then heads west, then south to the base of the final climb up to the West Rim. Behunin is to the south at the saddle before the trail to the West Rim begins climbing the slickrock slope.

Leave the West Rim trail and head south into Behunin.

Canyon
As you head down upper Behunin, a use trail cuts right, then reaches slickrock slabs. Traverse across, then work down the slabs. Follow the drainage bottom to the first rappel where the canyon drops in a big open slabby area (30 or so minutes from leaving the West Rim trail). At the first rappel, a series of several rappels comes in short order.

R1 - 30 m ( 99 ft. ) at the first drop, traverse right to a large ledge and anchor. Rappel two stages to a flat area. This is a low angle rappel.

R2 - 45 m ( 148 ft. ) From a large tree, rappel down slabs and short vertical sections.

R3 - 50 m ( 165 ft. ) down slabs and a steep section.

R4 - 40 m ( 132 ft. ) the rappel to the canyon floor.

Phew, down the initial series of rappels, it is easy walking as you head down canyon for the next 5-10 minutes.

R5 - 30 m ( 99 ft. ) - is a rappel into a pool. Or (as I prefer) follow a small trail on the right to a tree and 30 m ( 99 ft. ) rappel that avoids the pool.

It is easy hiking for a few minutes to R6.

R6 - 20 m ( 66 ft. ) - Follow a social trail on the right that leads down to a tree.

A section of nice narrows leads to the next rappel.

R7 - 30 m ( 99 ft. ) rappel where the canyon turns left. There will likely be some water to try and avoid here. A first stage comes to a pool after about 12 m ( 40 ft. ), continue down to a second set of pools for a total of a 30 m ( 99 ft. ) rappel.

The end of the canyon and final 2 rappels appear.

R8 - 45 m ( 148 ft. ) rappel down to a slot. Be careful of rope pull here, it is best to have the last person pull before coming down into the slot.

R9 - 50 m ( 165 ft. ) the final rappel from the slot. To reach this rappel, climb down under the boulder to the anchor. The rappel is mostly free, be sure to rig enough friction. Walk back away from the drop for easiest pull.

Exit (20-30 minutes)
Scramble down to the Emerald Pool trail. It reaches a junction. Left goes back to the Grotto stop where you started, or right more directly takes you to Zion Lodge.