Cave Stream

Cave Stream runs 594 metres through limestone, and the through-trip is one of the few caves in the country you can legally walk yourself with no guide, no permit and no fee. You enter at the downstream end, wade upstream against the current in water that is generally thigh-deep but can be chest-deep, climb a small waterfall on cut footholds near the top, and come out at the upstream entrance. It takes most people forty-five minutes to an hour in the dark. The reserve is genuinely serious about the risks, and so should anyone going in be: the water is around ten degrees year round, hypothermia is the main hazard, the cave floods without warning after rain, and there have been deaths. The minimum sensible kit is two torches per person, warm layers that work wet, sturdy shoes and a group of at least three. If the water at the entrance is discoloured or above knee height, do not enter.

What you actually see

• The through-trip - 594 metres of stream cave, walked end to end.
• The waterfall climb - cut footholds near the upstream end.
• The total darkness - no lighting of any kind inside.
• The free access - no guide, no permit, no supervision.

When to go

December to March, and only in settled weather. Do not enter if rain is falling or forecast, or if the water is discoloured or above knee height at the entrance.

Honest expectations

People have died here. Ten-degree water, flash flooding and hypothermia are the real risks. Take two torches each, go in a group of three or more, and be prepared to turn back. This is caving, not a walk.

Nearby

Castle Hill is a few minutes east; Arthur's Pass is west up SH73.