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Portroe Quarry
Ireland · wreck · beginner
3–39 mbeginnerOWshore entry
MEDIA5 items
Portroe Quarry
A flooded slate quarry in the Arra hills above Lough Derg: freshwater, no weather, a 5 m training platform, and cars, huts, a boat and a mine shaft stacked down to 40 m.
Max depth3–39 m
Required levelbeginner
Entry typeshore
Visibilitynot sourced
The dive
Portroe is not a sea dive. It is a disused slate quarry in County Tipperary, two kilometres back from the eastern shore of Lough Derg, flooded with fresh water and run as a dive centre since around 2010 — Ireland's first inland one. That is the whole point of it: it is divable regardless of what the Atlantic is doing, which is why clubs from Dublin, Galway and Cork use it for training, for technical and rebreather work-up, and for winter diving when the coast is shut.
Entry is off a walled ramp with steps. Depth runs from about three metres at the shallow end to 39 or 40 metres at the deepest, varying with the water level, and the operator gives the average as around 18 metres. A purpose-built training platform sits at 5 metres. Left of the entry ramp the ground averages 12 to 13 metres and holds two car wrecks and an underwater pub, along with building equipment, old wheels and a kayak. Following the quarry's original entry ramp to its end brings you to about 12 metres; carrying on down leads to the remains of old stone huts at 16 to 18 metres and then to a sunken boat at 18 metres, on a bottom of pure mud and silt that will take the visibility away if you touch it.
Dropping to the right of the platform puts you straight into 18 metres, close to the opening of an old mine shaft: the shaft mouth, the wooden sleepers laid across it and an old iron ladder are still intact, with the top of the sleepers at 27 metres. Out in the middle of the quarry a winch and crane structure is still fixed in the wall, permanently marked by a buoy, its top also at 27 metres. Below the winch the wall runs on to about 40 metres, where the operator's own description is blunt: boulders and small debris, very cold, very dark, and no reason to linger.
Conditions are freshwater and constant rather than seasonal. Reported visibility runs from three to fifteen metres, and winter water temperatures sit around 4 to 5.5 °C — a January 2024 reading was 5.5 °C. There is no marine life to speak of; the attraction is the man-made furniture and the reliability. Access is not free or open: the quarry is a private dive centre with membership, admission, a guest log book and weekend-only standard opening, and entering the water without that is both trespass and, given the depth and the silt, genuinely dangerous.
- Two car wrecks and an underwater pub at 12-13 m
- Old stone huts at 16-18 m and a sunken boat at 18 m
- Intact mine shaft with wooden sleepers and an iron ladder, top at 27 m
- Winch and crane still fixed in the quarry wall at 27 m, marked by a permanent buoy
- Training platform at 5 m and a step-in entry
- Divable in any weather, all year
Please note before you go
- Deep, cold, dark water: 40 m at the bottom in freshwater at roughly 4-5 °C
- Mud and silt bottoms around the boat wreck and below the mine shaft — easy to lose all visibility
- Old mine shaft with wooden sleepers across it: an overhead environment, not a swim-through
- Man-made structures (cars, pub, crane, huts) with entanglement and entrapment potential
- Freshwater and altitude: buoyancy and dive-computer settings differ from a sea dive
- Entering the water outside the dive centre's supervision is prohibited and has proved fatal at Irish quarries
Access & rules
Mandatory requirementsGetting there
Inland site in the Arra hills above Lough Derg, near Portroe village, Co. Tipperary. Published coordinates are 52°51'38.3"N, 8°21'29.4"W. From the motorway, exit junction 26 on the N7/M7 and follow signs for Tullamore on the N52 for roughly 15 km. Standard opening is Saturday and Sunday, 09:00 to 17:00. On site there are changing rooms, toilets, hot drinks, a sheltered kitting-up area, a classroom, two compressors and an air bank, a cover boat and oxygen. Contact the dive centre (diveportroe.com) before travelling.
Operator
Access to the site runs through a local operator.
Restrictions
Access is through the dive centre only. Divers must hold a current membership card and show diving qualifications, sign the guest log book on arrival, and pay a day admission. Published rates have been quoted between €25 and €30 for a day, membership at €25-30 a year and air fills at €5-6 per 12 L cylinder, so confirm current prices with the centre. Students may only dive with the instructor conducting their training. Swimming or entering the water without proper gear, training and centre supervision is prohibited.
Rules and permits
Private property operated as a dive centre. The owners fenced the quarry and dug trenches specifically to stop unauthorised access, and unsupervised entry is trespass as well as a serious safety risk. There are no marine-park rules here — this is freshwater and inland — but the centre's own membership and log-in requirements are conditions of entry.
Season
There is no season here in the usual sense — the quarry is sheltered, freshwater and divable in any weather, which is its entire reason for existing. The standard opening is weekends, Saturday and Sunday, with night dives run roughly monthly. Winter diving is perfectly practical but cold: around 4 °C in December to February, with a 5.5 °C reading logged in January 2024.
Conditions
Visibilitynot sourced
Currentnone
Surgeflat
WaterFreshwater
Depth range3–39 m
Environmentwreck
Crowdsmoderate
Flat, still, freshwater, and the same on a gale day as on a calm one. Reported visibility ranges from about three to fifteen metres. Winter water sits around 4 to 5.5 °C and stays cold all year at depth; the shallow platform warms a little in summer.
On current: None. This is a flooded quarry with no tide, no swell and no current at all, which is exactly why it is used for training and for skills work. The variable is water level: the operator notes the depth range shifts between roughly 7-8 m and 40 m depending on how full the quarry is, and the deepest published survey figure is 39 m. Silt is the real hazard — the bottom around the sunken boat and below the mine shaft is mud that will destroy the visibility for everyone behind you.
Dives & underwater footage
Questions & answers
How deep is Portroe Quarry?
From about three metres at the shallow end down to 39 or 40 metres at the deepest, with the exact range shifting as the water level changes. The dive centre gives the average depth as around 18 metres. Most of the man-made features sit between 12 and 27 metres, and below the winch the wall runs on to 40 metres over boulders and debris.
Is Portroe a sea dive?
No. It is a disused slate quarry in County Tipperary, about two kilometres inland from Lough Derg, flooded with fresh water and run as an inland dive centre. There is no tide, no swell and no current, and no marine life. That reliability in any weather is the reason Irish clubs use it for training and technical work-up.
What is there to see underwater at Portroe?
Man-made furniture, sunk deliberately or left over from the quarry. Two car wrecks and an underwater pub sit at 12 to 13 metres left of the entry ramp, old stone huts at 16 to 18 metres, a sunken boat at 18 metres, an intact mine shaft with wooden sleepers and an iron ladder with its top at 27 metres, and a winch and crane still fixed in the wall, also at 27 metres and marked by a permanent buoy.
Do I need a permit or membership to dive Portroe?
Yes. Access is through the dive centre only: you need a current membership card, must show your diving qualifications, sign the guest log book on arrival and pay a day admission. Published rates have run between €25 and €30 a day with annual membership at a similar figure, so confirm with the centre. Swimming or entering the water without gear, training and supervision is prohibited.
When is Portroe Quarry open?
Standard opening is Saturday and Sunday, 09:00 to 17:00, with night dives organised roughly once a month. Because it is freshwater and sheltered, it is divable in any weather all year round, which makes it the usual Irish winter and bad-weather option. Contact the centre before travelling.
How cold is the water and what should I wear?
Cold. Winter temperatures sit around 4 °C from December to February, with a 5.5 °C reading logged in January 2024, and the deep end stays cold year-round — the operator describes 40 metres as very cold and very dark. This is drysuit diving with a good undersuit, and a torch is essential below about 20 metres.
Is Portroe good for beginners?
Yes, that is largely what it is for. There is a purpose-built training platform at 5 metres, a step-in entry off the ramp, still water and no weather, and courses run at every level. Students dive only with the instructor conducting their training. The deep end and the silty sections around the boat and the mine shaft are not beginner ground.
What are the hazards at Portroe?
Silt is the main one — the bottoms around the sunken boat and beneath the mine shaft are mud that can take the visibility to nothing if disturbed, so stay off them and frog-kick. Beyond that: real depth in cold, dark freshwater, an overhead environment at the mine shaft, and entanglement risk around the cars, pub and crane structures. A cover boat and oxygen are kept on site.
Life at Portroe Quarry
This is fresh water, so there is no reef life to log. We do not carry an occurrence record for inland sites: the scientific databases we use are marine, and the nearest records would come from whatever lake or river is in the search radius rather than from the water you dive.
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