Abel Tasman Southern Loop

The Abel Tasman Southern Loop is an estimated 39 km (24.4-mile) circuit from Mārahau to Castle Rock Hut and back, joining the Coast Track at Tinline to the Inland Track and returning by the Anchorage descent. It is a visitor-made circuit linking marked tracks, not one signed loop, and no official total distance is published. The 15.1 km figure to Castle Rock Hut is the one-way approach from Mārahau; the full loop adds the inland retrace, Anchorage connector and coastal return. Allow about 11 hours of walking across two days and treat this as a demanding overnighter, not a long day walk. The hut is the route’s turnaround; the Castle Rocks viewpoint is a separate, steep spur beyond it.

From the Mārahau entrance, follow the wide, mostly easy Coast Track for about 2.7 km to just past Tinline campsite. Turn left onto the Inland Track. This first part is a useful warm-up, but it can make the next stretch feel like a different hike: the narrow inland path starts climbing almost immediately. If you only want a short coast walk, Tinline and back is a much easier outing; it doesn’t include the inland experience that makes this circuit.

The climb begins gently through regenerating native bush, then gets distinctly steeper for about a kilometre. There are occasional openings toward Anchorage and across Tasman Bay, but most of the way is a forest walk rather than a string of viewpoints. Around four kilometres after the Coast Track turnoff, a junction drops toward Anchorage; continue toward Holyoake Clearing, about 15 minutes farther on. The clearing sits at roughly 600 m and has a basic shelter. Water is scarce between Tinline and Holyoake, so don’t count on streams to refill you.

Beyond the clearing, the climb eases into rougher, rolling track through older bush, with short rises and dips through stream gullies. Roots slow you down, especially in the tree-rooted sections, and the path feels more like a tramping track than the well-formed coast route. Allow another two to three hours for the roughly 6 km to Castle Rock Hut. It stands in a small clearing at about 720 m, after a day that has climbed a long way from sea level. The forest is a good place to listen for tūī and bellbirds; weka have also been seen around the hut.

Castle Rock Hut has eight bunks and is first come, first served; it doesn’t take bookings. Its tap water is untreated, so it needs boiling or other treatment. Castle Rocks themselves sit on a separate spur: the outcrops are only a few hundred metres away as the crow flies, but the short path drops and climbs a steep, eroded slope. On a clear evening, the ridge opens over Mārahau Valley and Tasman Bay. That view is worth the extra effort if your footing is sure. The mapped 39 km circuit ends at the hut and leaves this viewpoint spur out of its mileage.

Retrace the rooty Inland Track to the Anchorage junction, then follow the descending connector through regenerating forest and scrub to the Coast Track. From there, the coastal walk south to Mārahau is long but gentler underfoot. Observation Beach is an optional detour from the coast; getting back to the main track means a short, sharp climb, and the detour isn’t included in the route or distance above. There’s no food stop on the circuit. If you stay in a Coast Track hut or campsite, book it in advance; Castle Rock Hut is the no-booking option. Dogs aren’t allowed on the Inland Track, so pets can’t join this route.