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Otter Hole


The access for caving trips into Otter Hole is managed by the Royal Forest of Dean Caving Club on behalf of the landowner. The access agreement requires all visiting groups to be accompanied by a warden. This is due to the unusual effects of the tide and the local weather on the tidal sump in the cave and also as a measure to protect the formations.

Bookings are not taken for paying groups or cavers under the age of 18. The warden may abort the trip at any time if they have concerns about the group.

All people entering the cave will be asked to prove they have public liability caving insurance.


"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" (Caves of South Wales guidebook)

The Warden is not responsible for looking after members of your team. It is your Club's responsibility to ensure that everyone in the group is capable and is suitably equipped for the trip.

Trips for 3-5 people can be arranged by contacting the Otter Hole Secretary (see contact details below)

If you would like to see what a trip in the cave is like and learn more about the history, Paul Taylor has made a dvd which may be of interest. Please contact Nicky for details if you're interested in purchasing a copy. Copies of the survey are also available at 5.

General Information

Grid reference: ST 5258 9615

Trips are usually restricted to one group at each time in order to avoid delays in the constricted entrance series and to protect the formations. A minimum of 3, maximum of 5 people per group is allowed (excluding the guide) There are 2 types of trip, an overtide trip, or a shorter between tide trip.

With an overtide trip, the sump is passed just as it is closing, allowing approximately 9-15 hours of caving before the sump opens. Nine hours usually allows the average group to get to the end of the cave and back.

A between tide trip passes the sump as it opens, and the group has approximately 6 hours before it closes again. Missing this deadline will result in waiting another 6 hours before an exit can be made. The average group will get to see the formations in the Hall of the Thirty, and maybe a little further. It is not usually possible to get to the end and back in this time.

As a very rough guide the trip times from the carpark and back are about 8 hours for a between tide, and 12 hours for an overtide trip.

Visitors should not underestimate the trip, although there is nothing particularly difficult in the cave, it is fairly arduous and sustained. Come prepared with water, food, and a balaclava.

Groups may be asked to contribute to the conservation work in the cave in some way: cleaning formations, laying tape or removing rubbish, etc. If you do wish to help in this way, your assistance is greatly appreciated!

Otter Hole can only be safely accessed during the summer months when the river levels are at their lowest. During the summer months high rainfall, high winds and the tidal range will also affect access. High surface water levels cause the tidal sump to become unpredictable. To minimise the chances of groups getting stranded on the far side of the sump, trips may have to be cancelled at short notice. If this is the case we will try to re-arrange a trip in the same season, but please bear in mind that this may not always be possible.

Booking The Trip

A Warden's meeting is held before the first trips in the season in order to discuss conservation matters and allocate wardens for the forthcoming trips. Bookings should ideally be made before this meeting (usually held in March) to assist the planning of trips for the year. Please note that all the wardens are volunteers. We will try to accomodate trips at shorter notice but please try to book your trip at least 3 months in advance.

The Booking Calendar 2020 shows the available trips for the coming season. Please choose your preferred date and type of trip from the list, and send your request to the booking secretary. Also try to give alternative dates if possible, to make it easier to allocate a guide. Don't forget to give a contact tel. no. If you have not received a reply to your request within 2 weeks (we have holidays occasionally !), please resend your email or contact the secretary by telephone or post.

2008 calendar available for information.

2009 calendar available for information.

2010 calendar available for information.

2011 calendar available for information.

2012 calendar available for information.

2013 calendar available for information.

2014 calendar available for information.

2015 calendar available for information.

2016 calendar available for information.

2017 calendar available for information.

2018 calendar available for information.

2019 calendar available for information.

Otter Hole secretary

Requests for trips, giving contact details should be made to the Otter Hole Secretary:

The Homestead,
Johnsons Way,
Gloucestershire GL15 4RZ
Tel: 01594 560185

Supporting Conservation Work and Cave Rescue

Large scale surveys are available for sale from the Otter Hole secretary, as well as from the wardens. These are priced at 5.00. The proceeds are used for maintaining the rescue dump in the cave. If you would like to buy a survey, it would be helpful to let the Otter Hole secretary know in advance so that surveys can be brought along on the day of your trip.

Overview and History

Possibly the most famous of all the area's caves, Otter Hole runs below Chepstow Racecourse, and contains some of the country's finest cave formations.

The entrance to the cave lies beside the banks of the River Wye, which is tidal at this point. The entrance series is affected by the rise and fall of the tides, which forms a sump for three hours either side of high tide. During very high tides, the whole entrance series can flood, a fact discovered by a group of explorers during the 70s who luckily managed to escape the rising waters.

One of the lasting memories of an Otter Hole trip is the incredibly thick, sticky estuarine mud that gets everywhere and refuses to be washed off. Once past the muddy bits, a couple of boulder chokes are negotiated before the formations begin, increasing in size and splendour until the Hall of the Thirty is reached, jammed with monumental stalagmites. The formations continue beyond the Hall of Thirty until the cave changes character at the junction of Tunnels Left and Right.


There is a gallery of photos. If you would like to share some of your own photographs, there is a flikr group set up for you to do so:
  • Otter Hole photo sharing

  • video of The Hall of 30 : by Nicky Bayley:

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