The Cave

  • Ogof Ffynnon Ddu, the Cave of the Black Spring, commonly known as OFD, lies under the NNR and stretches well beyond the reserve boundaries. At over 50km/32miles overall length, the cave is the third longest in the UK and at around 300m, or just under 1000ft, is the deepest by a significant margin.There are three entrances to the cave.
  • The lower entrance, known as OFD 1, was discovered in 1946 and lies just uphill from the dark stream resurgence that gives the cave its name.
  • The through trip from the Top to the Bottom entrance remains a classic in the UK, and its miles of passages provide everything from huge chambers, beautiful formations, to yawning chasms and thundering river passages.  
  • Access to the caves is confined to experienced cavers only. Information for cavers can be found by following the "Access" link above. There is underground access for non-cavers just across the valley at the National Showcaves Centre, Dan-Yr-Ogof (, one of Wales' most popular tourist attractions and part of another NNR. For anyone wanting to get into caving, more information can be found at 
  • More information on the Cave, including photographs and surveys can be found by visiting


Access to Ogof Ffynnon Ddu I, II, & Cwmdwr

The entrances to OFD I, II & Cwm Dwr are located on land owned by either Natural Resources Wales or South Wales Caving Club, access is administered jointly under a single access arrangement by means of a permit. Unless you are a member of a club with an annual permit, you will need to arrange this in advance by contacting the Ogof Ffynnon Ddu Management Committee Permit Secretary.

The cave entrances are gated, keys can be collected from SWCC HQ on production of a permit. Such permits are available, via the OFDCMC Permit Secretary, to members of clubs which are member clubs of one of the Regional Councils of the BCA. Permits are normally valid only for a specified date. The OFDCMC will consider applications for permits that are valid for one year but such permits are normally granted only to clubs that visit the cave frequently and have, over a significant period, demonstrated a responsible attitude to safety and conservation.


Access to the Columns ( in OFD II ) has been restricted since 1978 following a number of incidents of wanton damage to the area. The Columns and adjacent floor are particularly vulnerable because, being formed from limekiln seepage, they are much more fragile than conventional calcite formations. All parties visiting the Columns must therefore be accompanied by a Warden. Wardens will normally be available to accompany parties on the Sundays of the Easter, May Day, Spring, and August Bank Holidays, and New Years Day itself. Parties wishing to visit the Columns at these times do not need to make any prior arrangement, but should have a valid permit for OFD II and should make themselves known to the Warden by 10.00am on the day, either in person or by phone (01639 730613). Wardens will normally be available at The Columns between noon and 1500 each open day. It is to be noted that it is not the job of the Warden to lead parties to The Columns, only to meet by arrangement. Parties wishing to use the upper entrance must be suitably prepared with either ladders and lifelines or SRT kit. Please read the Access Conditions before applying.

Approach Route  you should not use the garden of the cottage at Y Grithig to get to Ogof Ffynnon Ddu I (Bottom Entrance). In addition, you should no longer use the previous route to the cave via the footpath (known locally as The Pant, x x x x on map below) which starts 150m or so past the houses as you go down the hill. Access to the cave entrance from the bottom of The Pant is no longer possible as you would be on private land which cavers do not have permission to cross. You should not park or change in the bottom lay-by or in the road leading past Y Grithig as there is no longer access via this route either.

If you are walking from the SWCC HQ: take the road down the hill, past the start of The Pant footpath on your right, and after about another 350m, just past Powell’s Cave, climb over the metal gate on your right. You can then descend across SWCC‑owned land to the entrance. There is no clearly defined path on this route but there are orange tape markers on trees to show the way – – – – on map below.

Entry Rules

Ogof Ffynnon Ddu Access and Entry: Conditions, Procedures and Rules

These are the latest Conditions, Procedures and Rules as adopted by the OFDCMC February 2015

These Access Procedures apply to all parts of and all entrances to Ogof Ffynnon Ddu.

  1. The Permit Secretary administers access to Ogof Ffynnon Ddu acting on behalf of the landowners, Natural Resources Wales and the South Wales Caving Club, via the OFD Cave Management Committee.  The entire cave is a Site of Special Scientific Interest (SSSI) and a large part of it is a National Nature Reserve.  Access to the cave is subject to the obligations placed upon the landowners by its special status.
  2. Entrances to the cave are gated and permits for entry are obtained from the Permit Secretary by following the procedures set out here. Conservation of the cave and its flora and fauna is a priority and cavers are expected to act responsibly and adhere to the entry conditions and rules.
  3. Access is available to members of bona fide caving clubs who have read, and are prepared to abide by, the Conditions of Entry and Rules published by the Cave Management Committee.  Bona fide caving clubs are defined as those affiliated to the British Caving Association or another appropriate national or international body. 
  4. Applications for permits must be made by an officer of the club and be received by the Permit Secretary at least two weeks prior to the proposed caving trip.  Applications may be made either by email to This email address is being protected from spambots. You need JavaScript enabled to view it. or by post, in which case a stamped addressed envelope would be appreciated. 
  5. The maximum permitted party size is 6 people, including the leader, and individual parties must remain separated in the cave.  A permit covers a single party of up to 6 people. If more than 6 people from the applying club will be in the cave at the same time then multiple permits must be requested. 
  6. Permit holders may obtain keys to the cave from SWCC headquarters at weekends or, during the week, from recognised key holders.
  7. The Permit Secretary shall have absolute discretion in interpreting these conditions and may refuse a permit, in which case the applicant will be informed of the reason for refusal. The applicant may appeal, in writing, to NRW and SWCC or directly to the secretary of the OFD Cave Management Committee, for consideration at its next meeting.
  8. There is a facility for Annual Permits to be issued to clubs that have demonstrated a regular and conscientious interest in Ogof Ffynnon Ddu. Applications for Annual Permits should be made to the Permit Secretary for discussion at the next meeting of the OFD Cave Management Committee. Clubs who have a rapid turnover of members (such as University caving clubs) are not normally granted annual permits.
  9. The South Wales Caving Club is normally granted automatically an annual permit for the cave within the NNR, in recognition of its location and special role in relation to the NNR.
  10. Access to the Columns area is restricted in the interests of conservation. Parties may visit the Columns only when a NRW Voluntary Cave Warden is present. Wardens will normally be available for visits to the Columns between noon and 3pm on the Sundays of Easter, May Day, Spring and August Bank Holidays, and New Year’s Day. These dates should be publicised by the Secretary who also draws up a rota of Wardens. Parties wishing to visit the Columns at these times do not need to make any prior arrangements but should make themselves known to a Warden by 10 am on the day.  Parties must ensure that they have their own leaders; Wardens do not act as leaders for visiting parties.
  11. The ‘Entry Conditions and Rules’, below, must accompany all permits issued.



  • These Entry Conditions and Rules apply to all parts of and all entrances to Ogof Ffynnon Ddu.
  • When the SWCC HQ is open, the destination board in cottage no. 8 lobby area must be used. A key-ticket, which includes the name of each person entering the cave, must be completed for rescue purposes. When the SWCC HQ is closed parties must make other arrangements for rescue. Note that the HQ is usually closed by 5pm on Sundays.
  • For reasons of cave conservation and adequate supervision of less-experienced cavers, the maximum permitted party size is 6 including the leader.  Parties must not join up underground and should deliberately maintain separation from other parties.
  • The leader is responsible for the conduct and safety of the party AND for the provision of the equipment necessary to complete the trip.  The leader must draw attention to the conditions relating to the use of any fixed equipment within the cave, which are displayed on the board in SWCC HQ.  (A copy of these will be given to mid-week users).
  • ONLY electric lighting is to be used. Carbide MUST NOT be taken into the cave.
  • This permit is for ENTRY ONLY. Camping, digging and the use of explosives, dye tracing and other research projects require special permission, for which application is to be made to the OFD Cave Management Committee.
  • Conservation of the cave is very important and those who enter the cave are responsible for its welfare. Some areas are taped off for conservation reasons. Marker tapes must not be crossed or moved, under any circumstances other than in extreme emergency. Observe all tapes and route markings in the cave. If there is no tape, proceed only if there is a clearly defined path. If in doubt, STOP. 
  • No litter whatsoever is to be left either inside or outside the cave.
  • Smoking is prohibited throughout the cave.
  • The gates are to be locked at all times except when entering or leaving the cave.
  • Cavers enter at their own risk.  Many sections of the cave are arduous.  For safety reasons, adequate experience and suitable clothing and equipment are required throughout the cave and especially in the further reaches of the cave and in the streamway.
  • Installations, apparatus and equipment must not be damaged.  If accidental damage occurs this should be reported immediately on return via the whiteboard in SWCC cottage no. 8 and by email to the Permit Secretary.
  • Access to the land surface of the NNR and of much of the remainder of the SSSI is unrestricted but visitors are asked to help protect the wildlife and natural beauty and avoid disturbance to grazing animals.
  • Failure to observe these conditions may result in the refusal of any future application to the OFD Cave Management Committee for entry to any part of Ogof Ffynnon Ddu.
  • These Entry Conditions and Rules may be revised from time to time by the OFDCMC.



Caves are a special and rare environment, some more so than others, and parts of some more so than others.

Active stream passages and potholes with fast moving water may have very little that can be accidentally damaged by the passage of a caver.

On the other hand, fossil cave passages where streams never flow are likely to contain all sorts of delicate remains that could be easily damaged by the passage of a single thoughtless caver. Where there is a risk of accidental damage, whilst passing delicate straw stalactites or sand banks, approaching close to a crystal pools, for example, you should slow down, look carefully around you and take extreme care.

All these features are easily damaged and cannot be repaired. The following is a carefully considered CODE intended to minimise damage to caves. Please read it and follow it whenever you go caving. Thank you.

1 CAVE WITH CAUTION and WITHIN YOUR OWN ABILITY and EXPERIENCE If you are the leader/organiser always be aware of the abilities/limitations of ALL of the members of the party. The ‘Weakest Link’ must dictate the speed and extent of your trip – not the strongest! Tired cavers will not only damage themselves, they will damage the cave as well!

2 KEEP PARTY SIZE Appropriate to the particular cave that you are visiting.

3 OBSERVE and KEEP TO TAPED ROUTES In taped-off sections follow the path and do not cross the tapes. They are there for good reason.

4 DO NOT TOUCH FORMATIONS OR OTHER DELICATE ITEMS These are easily broken or muddied – they must NEVER be touched.

5 KEEP AWAY FROM BATS OR OTHER LIFE Bats are endangered species – please keep away from all of them. You must not disturb them. All bats are protected by law.

6 NEVER DIG WITHOUT PROPER CONSENT Sand/mud banks are valuable sources of information about the cave and its surroundings, and might also contain archaeological remains. Do not dig or disturb without proper consent.

7 NEVER INTERFERE WITH SCIENTIFIC EQUIPMENT Dedicated cave scientists put a lot of time, funding and effort into their research. Never touch any such equipment that you find in a cave.

8 LEAVE NO LITTER OR POLLUTION Carbide lighting should never be used.

9 TAKE NOTHING OUT OF A CAVE Do not remove anything from a cave except your own or others’ rubbish.

10 TAKE PHOTOGRAPHS WITH CARE Do not be tempted to break any of these guidelines.

See for details of Regional Councils and BCA Officers

Do You Have Permission to Visit The Cave? Caves and their entrances are all owned by somebody.

The rights of the landowner should be observed at all times. If in doubt, ask!

You are responsible for any damage you may do!