Illaunabaha

Ireland · reef · advanced

6–30 madvancedAOWboat entry

Illaunabaha

A reef that dries out at low water, with a sunlit south face, a torch-only swim-through on the north side, and a long record of swell trouble.

reefwallswim-throughcaveboat

Max depth6–30 m

Required leveladvanced

Entry typeboat

Visibilitynot sourced

The dive

Illaunabaha is a reef running out westward from the cliffs a short boat trip north of Kilkee Bay. Kilkee Sub Aqua Club has been diving it since at least 1985, and the club's own account of it, written by Daniel Noel Gleeson, explains the name: he took the spelling off the Ordnance Survey maps, reads it as something close to Oileán na Bátha, and translates it in the vernacular as a rock awash — a rock that submerges at high tide and is therefore a hazard to shipping. Locals call the cliff formation behind it Aill na Bóthar. Parts of the reef are separated by watery gaps that open and close with the tide.

The south face is mostly vertical and often sunlit, with rockfalls that have left swim-throughs and niches. The dive centre works the east side, where the reef starts at 12 m and two slopes follow the wall down, one to 18 to 20 m and the other to a rock field at 25 to 30 m; they recommend diving it before midday, when the sun lights the reef wall. The north side is more sloping and barren, but Gleeson describes a long, narrow swim-through found there by a former club diving officer that runs from about 20 m up to 12 m, is a tight fit in places, needs a torch, and silts up behind the leading pair. It ends in a rectangular enclosure with overhangs where fish gather. On the seaward side at about 15 m is the stretch he calls the Gardens, broken rock faces and splits with far more colour than the depths below.

Dublin University Sub-Aqua Club dived a site here in 2009 that they spell Oileán na Beatha, in the same position and with the same features — a cliff jutting out with a cave underneath, and beside it a rock wall breaking the surface. They followed the wall down to about 20 m to a boulder field and reached 26 m, and remembered anemones in every colour. Their account puts the wall running north to south where Gleeson describes the reef pointing west, so the two disagree on the reef's axis even though they agree on almost everything else.

What matters more than the topography is the swell. Gleeson writes plainly that the area tends to get swells, and the club's own history here includes two bad days: a 1985 recovery in a rising southwesterly that half swamped the boat, and a June recovery of two exhausted divers who surfaced in white water in the corner between the reef and the cliff, near the cave, where the sea is funnelled. The club's answer is to brief divers to surface on the north side of the reef, which stays relatively calm in a southwesterly.

Vertical, often sunlit south face with rockfall swim-throughs
North-side swim-through from about 20 m up to 12 m — tight, and a torch job
The Gardens, broken rock and colour on the seaward side at about 15 m
Anemones in every colour on the wall, logged by DUSAC in 2009
Very large conger and lobster recorded here by the local club

Please note before you go

Swell: the club's own article says the area tends to get swells, and the sea swirls through gaps in the reef top
The corner between the reef and the cliff, near the cave, funnels swell — the club has had to tow divers out of white water there, and now briefs divers to surface on the north side in a southwesterly
Documented boat trouble: a 1985 recovery in a rising southwesterly took so much water aboard that the club had to bail by hand while motoring into the wind
Overhead environment: the north-side swim-through is a tight fit in places, needs a torch, and silts up behind the first divers through
Repeated depth changes over the reef top risk unplanned decompression, described in the club account as a decompression seesaw
Cold-water exposure — the same 1985 incident involved a diver who believed he was hypothermic
Boat only, on an exposed stretch of coast with no shore exit

Access & rules

Mandatory requirements

Certification required

AOW

Getting there

Boat only, a short run north out of Kilkee Bay past George's Head; DUSAC put the equivalent trip at 10 to 15 minutes from the harbour. Oceanlife runs the dive centre, shop and café at the East End pier and there is a slip and a large public car park beside it. For anyone bringing their own boat, DUSAC record that the slip is tidal (launch and retrieve within about three hours of low water on springs), that there are no public moorings, that local by-laws forbid compressing cylinders at the pier, and that the car park has a 2.1 m height barrier. Brief the boat on where divers will surface before anyone goes in: the club's standing answer in a southwesterly is the north side of the reef.

Operator

Access to the site runs through a local operator.

Season

Oceanlife on Kilkee's East Pier opens May to September, seven days a week, and Kilkee Sub Aqua Club is most active March to October. Gleeson's own diving here spans late September as well as high summer — he logged triggerfish on the reef in late September 2010 — so the shoulder works when the weather does. The limit is Atlantic swell, not water temperature or marine life.

Conditions

Visibilitynot sourced

Currentlight

Surgeheavy

WaterSalt water

Depth range6–30 m

Environmentreef

Coralnot sourced

Crowdsquiet

Cold Atlantic water on an exposed reef. DUSAC found visibility good enough in 2009 to remember the anemone colours, and describe Kilkee generally as usually extremely clear when you get out at all, though their 2023 trip rated it only alright. No source publishes a visibility or temperature figure for this site. The sun angle is a real variable rather than a nicety: the dive centre recommends diving before midday because that is when the reef wall is lit. Swell is the thing that decides whether the dive happens and where you surface.

On current: Tide matters here for a reason other than current: the reef is a rock awash, parts of it separate into gaps depending on the tide level, and the top comes up to around 6 m. The Kilkee sites themselves are recorded by DUSAC as non-tidal, with the dive boats working in and out all day, so there is no slack to plan for. The two accounts differ on maximum depth — the dive centre publishes a rock field at 25 to 30 m on the east side, DUSAC reached 26 m — so 30 m is the working maximum. Gleeson also warns that crossing the reef top and descending the far side puts you on what he calls a decompression seesaw.

Best months: May, Jun, Jul, Aug, Sep

Dives & underwater footage

Illaunabaha Dive · Z A

Questions & answers

How deep is Illaunabaha?

The reef top is around 6 m and dries or comes awash at low water. Kilkee Dive Centre works the east side, where the reef starts at 12 m and two slopes run down, one to 18 to 20 m and the other to a rock field at 25 to 30 m. Dublin University Sub-Aqua Club reached 26 m there in 2009, so 30 m is a fair working maximum.

Where does the name Illaunabaha come from?

Kilkee Sub Aqua Club's Daniel Noel Gleeson took the spelling off the Ordnance Survey maps and reads it as close to Oileán na Bátha. He translates it in the vernacular as a rock awash, the Admiralty chart term for a rock that submerges at high tide and is a danger to shipping. Locals call the cliff formation behind it Aill na Bóthar.

How dangerous is Illaunabaha?

Swell is the real hazard and the club has written up two bad days here. In 1985 a recovery in a rising southwesterly half swamped their boat, and on a later June outing two divers surfaced in white water in the corner between the reef and the cliff and had to be towed clear. The club now briefs divers to surface on the north side of the reef, which stays relatively calm in a southwesterly.

Is there a swim-through at Illaunabaha?

Yes, more than one. The south face has swim-throughs left by old rockfalls, and on the north side there is a long, narrow split running from about 20 m up to 12 m where another rock formation overhangs the main reef. It is a tight fit in places, needs a torch, and silts up quickly behind the first pair through, so the lead divers get much the better of it.

What will I see at Illaunabaha?

Kilkee Dive Centre describes crustaceans under rocks and in cracks — brown crab, spider crab and lobster — with sponges and anemones on the walls, and DUSAC remembered anemones of every colour on the 2009 dive. Gleeson logged the largest conger eel he has seen here and a very large pale lobster, plus triggerfish on the reef in late September 2010. Occurrence records around the pin add ballan and cuckoo wrasse, pollack, lesser-spotted dogfish and edible sea urchins.

How do you get to Illaunabaha?

By boat only, a short run north out of Kilkee Bay; DUSAC put the equivalent trip at 10 to 15 minutes from the harbour. Oceanlife runs the dive centre at the East End pier, beside a tidal slip and a large public car park. Clubs bringing their own RIB should note the slip's tidal window, the absence of public moorings, and the 2.1 m car-park height barrier.

Is Illaunabaha good for beginners?

No. The dive centre's own profile takes you to a rock field at 25 to 30 m, the north side has an overhead swim-through that needs a torch, and the site has a documented history of difficult surface recoveries in swell. Gleeson also warns that crossing the reef top and dropping the other side puts you on what he calls a decompression seesaw.

When is the best time to dive Illaunabaha?

May to September, when Oceanlife on the East Pier is open seven days a week; Kilkee Sub Aqua Club runs from March to October and has dived the reef into late September. The dive centre also recommends going before midday, because that is when the sun lights the reef wall on the south face.

Life recorded at Illaunabaha

60 species within 1.5 km · OBIS

Asterias rubensoccasional · 9 records

Cliona celataoccasional · 8 records

Marthasterias glacialisoccasional · 7 records

Pachymatisma johnstoniaoccasional · 7 records

Luidia ciliarisoccasional · 6 records

Echinus esculentusoccasional · 6 records

All 60 species recorded in this area

Species	How often	Records
Asterias rubens	occasional	9
Cliona celata	occasional	8
Marthasterias glacialis	occasional	7
Pachymatisma johnstonia	occasional	7
Luidia ciliaris	occasional	6
Echinus esculentus	occasional	6
Calliostoma zizyphinum	occasional	6
Obelia geniculata	occasional	5
Dysidea fragilis	occasional	5
Steromphala cineraria	occasional	5
Cancer pagurus	rare	4
Maja squinado	rare	4
Gymnangium montagui	rare	4
Pollachius pollachius	rare	4
Labrus bergylta	rare	4
Hemimycale columella	rare	4
Polymastia boletiformis	rare	4
Mytilus edulis	rare	4
Patella pellucida	rare	4
Amphilectus fucorum	rare	4
Labrus mixtus	rare	4
Holothuria forskali	rare	4
Scyliorhinus canicula	rare	3
Necora puber	rare	3
Taurulus bubalis	rare	3
Axinella dissimilis	rare	3
Stelligera stuposa	rare	3
Halichondria (Halichondria) panicea	rare	3
Haliclona (Rhizoniera) viscosa	rare	3
Clavelina lepadiformis	rare	2
Aplidium punctum	rare	2
Homarus gammarus	rare	2
Henricia oculata	rare	2
Aslia lefevrei	rare	2
Parablennius gattorugine	rare	2
Suberites carnosus	rare	2
Tethya aurantium	rare	2
Cadlina laevis	rare	2
Myxilla (Myxilla) incrustans	rare	2
Galathea strigosa	rare	1
Aglaophenia pluma	rare	1
Obelia dichotoma	rare	1
Lafoea dumosa	rare	1
Leuckartiara octona	rare	1
Nemertesia antennina	rare	1
Nemertesia ramosa	rare	1
Sertularella gayi	rare	1
Sertularia argentea	rare	1
Stichastrella rosea	rare	1
Psammechinus miliaris	rare	1
Trisopterus minutus	rare	1
Thorogobius ephippiatus	rare	1
Centrolabrus exoletus	rare	1
Ctenolabrus rupestris	rare	1
Axinella damicornis	rare	1
Axinella infundibuliformis	rare	1
Bubaris vermiculata	rare	1
Halicnemia patera	rare	1
Iophon nigricans	rare	1
Raspailia (Raspailia) ramosa	rare	1

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Biraghty Mor0.4 km

An offshore rock north of Kilkee whose wall runs from a boulder field at about 30 m all the way up to the surface.

Chimney Bay0.9 km

A gently sloping kelp-and-boulder bay on the far side of George's Head, and the Kilkee site that stays divable when the others do not.

Middle Rock2.1 km

The Kilkee wall you dive as one long ascent: cracks and overhangs from 35-40 m with something to look at all the way up to 6 m.

Outer Rock2.1 km

The seaward rock of the Kilkee pair, listed by the local club as its own boat dive and summed up in four words: only for the curious.

Newfie2.5 km

Kilkee's shallow training reef off the Duggerna Rocks — a sand runway from 2 m, kelp on top, and about 10 m at the deepest.

Donegal Point3.0 km

A through-cavern under a small headland north of Kilkee: in at 14 m, dark at 18 m, out at 24 m on the far side.

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