The entrance is situated in the bank of the River Wye near St.Arvans. From Chepstow, take the A466 towards St.Arvans and then Tintern. About 1.6 km outside St.Arvans, at the top of a wooded hill, is a forestry commission car park at Wyndcliff on the right. A track leads from the car park, down through the trees, towards the Wye. Go past a pump house and then over a log bridge. Just beyond the bridge a rough track on the left descends steeply to the river. Follow the track along the river bank to a small cliff. The entrance to the cave is at the foot of the cliff.
The cave is gated and access controlled to preserve the cave and its decorations.
The first sump (Tidal Sump) is affected by the level of the River Wye outside. The sump closes approx. 3 hours before high tide and opens again 3 hours after high tide. It is not normally free-diveable. The times of the tides can be found in Arrowsmith's Tide Tables for the Bristol and Channel Ports. If these are not available, ask for tidal information when writing for access. The cave should not be entered on high tides of more than 14.9 metres as the entrance series floods.
See the Access p.of the Cambrian Caving Council Website for current Access arrangements at http://www.cambriancavingcouncil.org.uk/restricted access caves.html
Description
The cave is one of the most serious undertakings in the country, mainly due to the complications of the tidal sump, and should only be attempted by experienced cavers. There are also several instances of cavers being ill after a trip in the cave, the source of the illness being as yet unknown. However, the cave is probably the most beautifully decorated cave in the UK, and well worth braving the hazards.
The walk-in entrance leads quickly to a climb up into a bedding plane on the left. At the end of this is a climb down into a lower, extremely muddy, bedding plane. The bedding plane contains pools and a large plastic pipe which is used for rescue purposes. The way on is to follow the pipe - it is only necessary to leave the pipe in two places, at a tight squeeze and at a climb over a boulder. The bedding plane emerges into a small chamber and the way on is via a rift on the right known as Fossil Passage. It is worth memorising this section for the return journey as the way back is not obvious. Fossil Passage is followed via a very slippery 2.4 m climb and a step over a hole to a long section of muddy walking and crawling past mud stained formations to the Tidal Sump. This can be passed as the tide is going down by swimming across to an eye hole or you can wait for half an hour or so and walk through the bottom.
There is an extensive series of passages beyond the tidal sump and some are finely decorated. cf FODCCAG
History
Hydrology
Conservation
SSSI: 0460 Pierce, Alcove and Piercefield Woods (Biological)
records