Submarine Wrecks in Ireland

Lying in just 12 metres of water off Bracklesham Bay, HMS A1 holds a unique place in British naval history: she was the very first submarine designed and built in this country for the Royal Navy. Constructed by Vickers in 1903, she had already survived one sinking — a collision with SS Berwick Castle in 1904 that killed eleven crew before she was raised — when she was repurposed as an unmanned torpedo target. In August 1911, operating on automatic pilot, she sank for good off Selsey Bill. Tidal currents slowly dragged her five miles along the seabed to her present position. The hull is virtually intact, with the bow standing proud while the stern disappears beneath a sandbank. Protected under the Protection of Wrecks Act since 1998, she requires a permit to dive, and the Nautical Archaeology Society has established a structured dive trail for visiting divers. For anyone interested in submarine heritage, there is no more historically significant shallow dive in British waters.

The crew of UC-42 were laying mines to destroy other ships when one of their own mines destroyed them. On 10 September 1917, this German UC II-class minelaying submarine was deploying a minefield at the entrance to Cork Harbour off Roches Point when a mine detonated, killing all 27 crew instantly. The wreck was relocated by divers in 2010 in approximately 28-30 metres and subsequently designated a war grave under the National Monuments Acts. She rests on her port side with the keel visible and an external bow torpedo tube lying in the silt beneath. In 2024, divers from Blackwater Sub Aqua Club and Mizen Archaeology recovered one of the propellers after months of careful excavation -- a significant maritime heritage event covered by RTE and the Irish Examiner. A licence under the National Monuments Acts is required to dive this protected site.

On 28 October 1918, with the Armistice barely a fortnight away, UB-116 attempted one of the war's most audacious submarine operations: a solo penetration of Scapa Flow through the mined entrance at Hoxa Sound to attack the British Grand Fleet at anchor. She never made it. British hydrophone operators tracked her approach and detonated a remote-controlled mine that killed all 34 crew — the last U-boat lost in the First World War. Raised in 1919, she broke free and sank again at the mouth of Pan Hope Bay; a controlled explosion later dealt with her remaining live torpedoes, and the blast left her barely recognisable as a submarine. What remains is a scattered field of torn steel and bent piping in 26 to 32 metres, with the conning tower standing as the only clearly identifiable feature. Orientation is challenging, but the story gives every twisted plate its weight. This is the physical full stop at the end of the U-boat war.

There is truly nothing else like HMS M2 anywhere in the world. Originally completed in 1919 as a submarine monitor carrying a massive 12-inch gun, she was converted in 1927 into the world's first undersea aircraft carrier, fitted with a watertight hangar and catapult for a tiny Parnall Peto floatplane. On 26 January 1932, during a routine exercise off Portland, water flooded through the hangar and she went down with all 60 hands. The salvage investigation found those hangar doors standing open — a haunting detail that has fuelled debate ever since. She rests upright and intact at around 33 metres in Lyme Bay, her 90-metre hull still unmistakably that of a submarine, the cylindrical hangar forward of the conning tower instantly recognisable. As a designated war grave she demands the utmost respect, but for those qualified to make the dive, she offers a genuinely unique encounter with a one-of-a-kind vessel.

At 43 metres on a rocky seabed near Baltimore, a German U-boat sits almost perfectly intact -- torpedoes still loaded in their tubes, the periscope glass unbroken, the Walter snorkel standing upright after eight decades on the bottom. U-260 was a Type VIIC submarine that struck a British mine approximately 32 kilometres south of the Fastnet Rock on 12 March 1945. The entire crew survived and were interned in Ireland for the rest of the war. Apart from mine damage to the bow, the hull is remarkably preserved. Open hatches allow limited penetration. The conning tower, twin bronze propellers, and DF aerial all remain in place. Visibility ranges from 5 to 10 metres. For advanced divers visiting Baltimore, West Cork, this is an unmissable dive -- compact enough to navigate the entire submarine in a single outing.

Visibility can exceed 40 metres here -- some of the clearest water on the planet, thanks to the rock and shale seabed off the Donegal coast. SM U-89 sits at approximately 62 metres depth, 25 miles off Malin Head, remarkably well preserved with deck guns at both bow and stern and torpedoes still in storage. She surfaced just 200 yards ahead of the cruiser HMS Roxburgh on 12 February 1918. The cruiser rammed the conning tower without hesitation, sending U-89 to the bottom with all 43 crew. Large cod, pollock, and conger eels patrol the wreck. Diving is from specialist charter boats out of Malin Head using trimix, with bottom times of around 30 minutes and total run times of 85 minutes. Designated war grave.

She nearly changed the course of the war. U-2511 was the only operationally deployed Type XXI "Elektroboot" submarine in World War II -- the revolutionary design that could have devastated Allied shipping had it entered service earlier. Commanded by Korvettenkapitan Adalbert Schnee, she made one war patrol and had a British cruiser group in her sights before the ceasefire aborted the attack. Surrendered at Bergen, Norway, she was scuttled by Royal Navy gunfire on 7 January 1946 during Operation Deadlight after her towing cable parted. Discovered in 1999 by local diver Al Wright, the wreck at 67-69 metres off Malin Head is largely intact on her port side, with a large blast hole on the starboard side near the conning tower. One of the most historically significant U-boat wrecks anywhere. Featured on BBC Dig WW2 with Dan Snow.