Over 564 dead -- the greatest single loss of life in the Irish Sea, and one of the most devastating maritime disasters of World War I. On 10 October 1918, UB-123 fired three torpedoes at the RMS Leinster near the Kish Bank. The first missed. The second struck the port side. As Captain Birch tried to turn back toward Kingstown, the third torpedo cut the ship almost in half. Twenty-one of 22 postal sorters aboard perished. The City of Dublin Steam Packet Company mail steamer, built in 1896 at Birkenhead, now lies at 28 metres approximately 4 nautical miles east of the Kish Light. The bow stands proud of the seabed; the rest is largely collapsed into sand. The anchor, recovered in 1991, is displayed at Carlisle Pier, Dun Laoghaire. Strong currents and poor visibility make this an advanced dive. War grave.
At approximately 09:50 on 10 October 1918, Kapitanleutnant Robert Ramm of UB-123 fired three torpedoes at the Leinster near the Kish Bank lightship. The first missed ahead. The second struck the port side forward, near the mailroom. Captain Birch attempted to turn the ship back toward Kingstown. The third torpedo struck the starboard side, causing a catastrophic explosion that cut the ship almost in two. She sank in minutes. Of those aboard — passengers, crew, military personnel, and postal workers — at least 564 died. Many drowned trapped below decks or in the water awaiting rescue. UB-123 was likely lost to a mine in the North Sea on or about 19 October 1918.
RMS Leinster is a passenger liner wreck located off Dublin, Ireland at a depth of 28 metres. The vessel was lost due to Torpedo (UB-123) in 1918. The wreck is diveable.
RMS Leinster lies at approximately 28 metres depth, 4 NM east of Kish Light, ~22 km from Dun Laoghaire.
RMS Leinster was lost due to Torpedo (UB-123) on 10 October 1918 during World War I, off Dublin, Ireland. 500 people lost their lives.
Diving the RMS Leinster is rated advanced and is requires an Advanced Open Water certification with wreck diving experience.
The best months to dive RMS Leinster are May, June, July, August, September. Water temperature ranges from 7°C in winter to 15°C in summer.
RMS Leinster is accessed by boat from Dun Laoghaire, Dublin, Ireland. The wreck is a designated war grave.
| Month | Temp | Visibility | Access | Marine life |
|---|---|---|---|---|
| Jan | 7.0°C | 3.0m | poor | Minimal — winter conditions |
| Feb | 7.5°C | 3.0m | poor | Minimal — winter conditions |
| Mar | 8.0°C | 4.0m | poor | Minimal — winter conditions |
| Apr | 9.5°C | 5.0m | marginal | Moderate — season starting/ending |
| May | 11.0°C | 7.0m | good | Good — wrasse, pollock, crabs, anemones |
| Jun | 12.5°C | 8.0m | good | Good — wrasse, pollock, crabs, anemones |
| Jul | 14.0°C | 9.0m | good | Peak — seals, large shoals, nudibranchs, conger eels |
| Aug | 15.0°C | 9.0m | good | Peak — seals, large shoals, nudibranchs, conger eels |
| Sep | 14.0°C | 8.0m | good | Good — wrasse, pollock, crabs, anemones |
| Oct | 12.0°C | 5.0m | marginal | Good — wrasse, pollock, crabs, anemones |
| Nov | 10.0°C | 4.0m | marginal | Minimal — winter conditions |
| Dec | 8.5°C | 3.0m | poor | Minimal — winter conditions |
6 evidence records from 6 sources.
Current research shows that 564 people were lost. Greatest loss of life in Irish Sea. 21 of 22 postal sorters aboard perished.
Over 500 lives lost. Greatest single loss of life in the Irish Sea.
RMS Leinster at 28m, 4 NM east of Kish Light. Advanced dive.
UB-123 fired three torpedoes. First missed, second struck port side, third struck starboard side cutting ship almost in half. At least 564 killed.
Torpedoed by UB-123. Bow pointing south, stands proud of seabed. Strong tidal currents. Neap tides at slack water.
In 1991 the anchor was raised by local divers and placed near Carlisle Pier, officially dedicated 28 January 1996.
4 NM east of Kish Light, ~22 km from Dun Laoghaire