From the Whitehorse Hill car park, follow the Hooker Valley Track.
Just before you reach Hooker Lake, the Ball Pass route is signposted, branching to the right off the main trail.
The ground trail leads above the moraine wall, reaching a large shingle fan which provides a good campsite.
From the shingle fan, the route continues up a distinct gully to the north-east, which is filled with snow in spring. The gully leads to a large shoulder below Mt Mabel known as the 'Playing Field', which provides an ideal camping site – water is often available near the top of the gully.
From the 'Playing Field', head up the shingle slopes to the east, which forms a large zig-zag between bluffs. Once above the zig-zag, follow an exposed ledge to the north to a small shoulder on the ridge north-west of Mt Mabel. This is one of the few routes through the bluffs and it is important to gain this point sufficiently high enough.
Traverse from this point in a northerly direction across rock slabs and then descend around the spur, west of Mt Rosa. Once past Mt Rosa ascend the shingle slope (this may be a snow field at certain times of the year) in a north-easterly direction to Ball Pass, the lowpoint at the top of the gully.
After crossing Ball Pass, the route descends over Ball Glacier for about 60-70m before turning south to gain Ball Ridge, to the right. Descend Ball Ridge to the privately-owned Caroline Hut, used by guide operators. The ridge has spectacular views of the Caroline Face of Aoraki/Mt Cook.
The trail then descends several rock steps, following the ridge crest. Two difficult sections can be avoided by turning around to the eastern side of the ridge. Follow the track markers to the level part of the track on the narrow ridge line. Do not follow the historic track further along, as slips have made it impassable.
Descend the boulder scree to the east. The route continues through alpine scrub. Follow the trail to the old Ball Hut site and over to Ball Flat. From Ball Flat, head down the Tasman Valley, following the old Ball Hut road to the end of the valley.
Note: Ball Pass Crossing is best attempted between December and March. Check conditions at the DOC Visitor Centre in Aoraki/Mt Cook Village, as the route is prone to landslides and avalanches