From the main Petra entrance and ticket office, head down the Siq to reach the famous Petra Treasury appearing through the narrow slot canyon. Continue around to the right and follow signs up to the “High Place of Sacrifice”, where you take a left turn up a set of stairs before reaching the Theater. Follow the winding steps all the way up to the ridge where the High Place of Sacrifice is accessible by a short footpath slightly off route to the right. Follow the well-developed trail down the other side following the sign for Wadi Farasa, passing the Lion Fountain and Garden Tomb.
Turn left off the main Petra trail onto a faint footpath (easy to miss, so GPS attention recommended). Follow this track as the path becomes more defined, turning south with large rugged mountains on your left. Continue on to the flatter area known as “Stuah Nebi Haroun” with its cultivated fields. Find and follow an old Roman Road heading down to your left along the ridge on the east side above Wadi Sabra, zigzagging down to the valley floor. Continue straight along the wadi, finding the easiest walking surface either along the side or the wadi bed. Reach the Sabra Amphitheater at 11.7km, a good place to take a rest.
From the Sabra amphitheater, continue along the way and cross to the west side of the wadi, passing through crumbling ruins of a fortress, with the path starting to erode away (if easier, stay down in wadi). Continue down Wadi Sabra as it deepens and the rock walls on either side rise higher and higher. Pass through areas of white sandstone, and pay close attention to find cairns on the right side marking a faint donkey path winding up the right side of the wadi, which provides a way around the massive dry waterfall in the wadi below. Take care on this path as it’s high above the wadi floor and can be a little rocky, but overall is a well-built trail and is even passable by a donkey. Follow this breathtaking path to see the huge view of the wadi’s drop near the waterfall, and continue along the side of the wadi for a section until the valley starts to open up, and the path follows closer to the wadi bed. More plants and a wet section of the wadi could provide water in an emergency, but be sure to filter before drinking.
Follow the main route of Wadi Sabra for approximately 3km, and take the best walking path you find along the way, which changes between the sides of the wadi and the wadi bed. When you see a 4×4 track rising steeply out the east/left side of the wadi, take this track up and head more southwest across small gulleys, leaving and crossing the 4×4 track and a paved road to reach the campsite in the area called Gas’ Mriebed, near scattered bedouin camps and areas growing crops nearby. The area is accessible by the paved road from Wadi Musa, which takes 1.5 hours each way.
Entry to Petra requires a pass, which can only be purchased at the front entrance. This route does not approach Petra through this entrance, so a pass must be purchased in advance.