UB 21
Protected Area
Sinah Common
Why dive here
With 176+ marine species recorded in the area - including blue sharks, dolphins, dwarf minke whales, humpback whales and ocean sunfish (mola mola) - UB 21 offers some of Cornwall & Devon's richest wreck diving. Water ranges 10-18°C, warmest July, August, September.
UB 21 isn't a deep dive, sitting at a comfortable 5 metres, making it approachable for most divers. This Coastal Class submarine, sunk in 1920 on its way to the breakers, stretches out 36 metres long, so there's a fair bit of wreck to explore. We've seen conger eels make homes in the nooks and crannies, and sometimes you'll spot lobsters tucked away. It's a solid wreck dive for those looking for something shallower, perhaps as a second dive, without a strong current, so it’s less about big pelagics and more about the wreck itself and the smaller creatures living on it.
Typical UB 21 Dive Profile
Illustrative profile based on site depth and type. Actual dive profiles vary - always follow your dive computer and training.
Safety Notes
Wreck site - avoid penetration without wreck diving certification. Watch for sharp metal and entanglement hazards.
Nearest Dive Centres to UB 21
Dive shops near UB 21
In2 Diving
Sussex Diving & Leisure
Mulberry Marine Experiences CIC
Andark Diving
Abyss Scuba School
Sunken Dreams Scuba Diving Academy
Reviews for UB 21
Conditions
Ocean conditions, forecast and tides for UB 21
UB 21 Ocean Conditions
Monthly averages for UB 21, sourced from Open-Meteo marine data - nearest station: Open-Meteo marine grid (50.44, -2.73) (3km away)
October Averages
Sea Temperature
17°C
62°F · Range: 15.1–17.5°C
Air Temperature
13°C
56°F
Wind Speed
8.14 m/s
15.8 knots
Atmospheric Pressure
1011 hPa
Based on 4 years of monitoring data · Data sources: Open-Meteo marine data
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