HMS Colossus Dive Trail Revitalised
Historic England and volunteer divers have revitalised the HMS Colossus dive trail, clearing marine growth and adding new diver trail stations to improve access to the Protected Wreck Site.
Built in Gravesend, Kent in 1787, HMS Colossus was a 74-gun Royal Navy warship that sank off the Isles of Scilly in 1798.
Historic England and volunteer divers have also captured striking new photography that reveals both the historic remains and the thriving marine life that surrounds them.
Licensed divers and armchair explorers alike can visit the Protected Wreck Site of HMS Colossus, following improvements ahead of the 2026 dive season.
Historic England commissioned volunteer divers from Cornwall and Isles of Scilly Maritime Archaeology Society (CISMAS) to refurbish the trail, helping make the site more accessible to both visiting divers and virtual audiences.
Exploring a piece of naval history
During its 11-year service, HMS Colossus saw action at Toulon, Groix, Cape St. Vincent and Cadiz.
In December 1798, while sheltering from a storm off the Isles of Scilly, the ship's anchor cable gave way and it was driven onto shallow ground off Samson, the largest uninhabited island off the southwestern tip of the Cornish peninsula.
All but one of the 595 people on board were rescued. HMS Colossus later broke apart, scattering its remains across the seabed.
The ship is also known for carrying part of 18th-century British diplomat and antiquarian Sir William Hamilton's collection of ancient Greek pottery. Some 30,000 pottery fragments recovered from the wreck site are held by the British Museum.
What the diver trail offers
The refurbished trail features two circular routes taking in the major features of the wreck, with numbered seabed stations and an improved waterproof guide. Clear waters, abundant marine life and well-preserved remains make the site one of England's most rewarding heritage dives.
Divers can see the remains of muskets scattered across the seabed. Cannon can be seen standing almost upright on the seabed, having crashed through the gun port when the ship turned on its side. Some of these guns are 2.75 metres (9 foot) long and weigh almost two tonnes each.
For those unable to visit in person, an interactive virtual tour mirrors the underwater trail, combining detailed 3D models, dive footage and photography to bring HMS Colossus to life.
HMS Colossus Protected Wreck Site
HMS Colossus is one of England's 57 Protected Wreck Sites. It has been granted the highest level of protection under the Protection of Wrecks Act 1973. This means that only licenced divers can visit it.
The diver trail at HMS Colossus offers a great opportunity to explore the remains of an 18th-century warship, with timbers, cannons and other features still visible on the seabed. The volunteer divers from CISMAS have worked incredibly hard to improve the trail, document the site and help make this remarkable piece of England's maritime heritage more accessible to divers and non-divers alike.
If you only ever dive on one historic wreck site, make it this one. To swim along the line of cannons standing upright on the seabed with their muzzles buried in the sand, still within their gunports, is a unique experience.
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