Sea Caves in Shetland

Da Hol's o' Scraada, Eshaness. This is a collapsed sea cave.

With more than 1,700 miles of coastline to explore it is no surprise that the shores around Shetland have amongst the most dramatic coastal scenery in Britain. With the second-highest sea cliffs in the UK, more caves than you can shake a stick at and natural arches to rival the Arc de Triomphe, it’s little wonder that Shetland is a bucket-list goal for those in search of a bit of adventure.

This blog post is a bit of an escape from the norm for me as I put the question to you – what would you like to hear about?

So, I’ve collected a few of your responses and will endeavour to answer as many as possible. I will include relevant links that you might find useful while planning your next Shetland adventure. Thank you for your suggestions!

Eshaness, Shetland, where some of the most accessible sea caves and collapsed sea caves can be found.

I’m interested in the sea caves and the partly collapsed sea caves (gloups?).

Shetland is a fantastic place for sea caves, at almost 1,700 miles long Shetland’s ‘jigsaw’ shaped coastline makes it a great place for exploring. Much of this comes from the diverse geology that makes up our islands and the fact that Shetland, sitting on the edge of the continental shelf, is a ‘drowned landscape’. After the last period of glaciation (about 10,000 years ago) Shetland became semi-submerged as sea levels rose. Also, the weight of melting ice caused Scotland and Norway to rise, in turn, pulling Shetland down (this is a process known technically as isostatic rebound).

A gloup is indeed the Shetland word for a “sea cave or cavern, the top of which has fallen in at the landward end.” Examples of these are most readily seen at Eshaness in Shetland’s north-west corner where the volcanic rocks have been prey to the erosive action of the often fierce North Atlantic.

Walking along Calder’s Geo (after parking at the lighthouse) you are tracing the perimeter of an old sea cave that has seen the collapse of the roof, creating a geo (a cleft in a rock). If you continue along the Eshaness Circular walk (details of which can be found here), you will come to the Hol’s o’ Scraada, a collapsed sea cave inland from the sea. It is called the ‘Hols’ (holes) because at one time there were two holes, but sometime in the early 20th century, the land bridge separating the two collapsed so now it is one large void in the land. It is an exceptional place to visit as the sea washes in on a stony beach inland from the coast.

A waterfall descends into the Hols o' Scraada, Eshaness.

Local photographer and thrillseeker, Ryan Leith, uploaded some fantastic footage of the Calder’s Geo sea cave on YouTube and you can view that here.

The cave at Calder’s Geo is said to be Britain’s largest sea cave following a recent scientific study of its inner chambers. Geologist Jonathan Swale used a laser range-finder to discover the true dimensions of the cave and found it to be 60ft tall and spanning a floor area of 5.600 square metres. This makes it one-and-a-half times bigger than the cave at Cheddar Gorge in Somerset. If you fancy a go inside this cave, you’ll need a calm day and a kayak!

Ryan is also on Instagram, and you can follow his adventures here.

There are many fantastic examples of sea caves in Shetland and another great cave to visit, with access into the cave via a rope ladder, is on the mainland. The Smuggler’s Cave in Burra is a fantastic coastal walk and is now well signposted on the cliffs (the entrance was often hard to spot before a sign was placed). You can read more about the Smuggler’s cave here.

It’s unclear why it is called the Smuggler’s Cave as there is no evidence it was used for smuggling – although that’s not to say it wasn’t used for this! It may have been used by locals to hide from the Press Gang during the 19th century, or, it was just lovingly called the Smuggler’s Cave by children with an appetite for imagination and adventure!

a walk to the smugglers cave

Another exciting cave is the Orkneyman's Cave in Bressay. Slightly less accessible this cave can only be explored by boat or kayak. If you take a trip with Seabirds-and-Seals and weather allows then access into the cave can be achieved. You can find out more about their boat trips here.

I had the pleasure of visiting this cave – large enough to moor a boat – with the Mousa Boat (for bookings and charter trips visit their website here). Skipper Darron (who I highly recommend!) skillfully took the 11.5-metre twin-engine Class VI boat into the cave and turned her in a full 360° circle inside, much to the surprise of the shags nesting inside the dark cavern.

Inside the Orkneyman's Cave, Bressay with the Mousa Boat.

The Orkneyman's Cave may seem like a strange name for a cave in Shetland, not Orkney. My favourite explanation for the name comes from folklore where, it is said, that an Orkneyman hid out in the cave after becoming shipwrecked while fleeing from the Press Gang and so gave it its name.

Another, perhaps more likely, meaning for the name comes from its old name Orknis Geo, or, the cave of the grey seal. The place-name for Orkney comes from the Old Norse word orkn or the Seal Island. Alternatively, according to Angus' Glossary of Shetland Place Names, it could come from the Gaelic for orca, or whale, and the Old Norse ey meaning island – giving Orkney (whale island), although this seems less likely.

Whether or not a shipwrecked Orcadian did hide out in the cave is unknown but, it makes a grand story nonetheless!

You can see footage of the Orkneyman's cave here.

Hol o Bordie, Papa Stour (300 metres) is thought to be the 4th longest sea cave in the world. Photo: Ryan Leith.

The island of Papa Stour, on Shetland’s Atlantic west coast, is also a fantastic place for stunning seascapes and sea caves and these are best explored by kayak. However, a walk around the coastline throws up some fascinating geological formations and Insta-worthy captures. The coast is peppered with rock arches, stacks and skerries as well as the caves and notorious Vee-Skerries that have seen many-a-tragic shipwreck over the years. Hol o' Bordie sea cave is thought to be the fourth-longest sea cave in the world at 300 metres long. You can see footage inside the cave here. Because of the wide-ranging variety of species the island supports, it has been designated a marine Special Area of Conservation.

Ryan Leith also has videos on YouTube exploring the sea caves of Papa Stour. These can be found here.

Some of Papa Stour's coastal formations.

By far and away the best way to visit some of Shetland’s vast array of sea caves, geos and inlets is on the water, and a kayak allows unparalleled views into some of these underwater meccas. Sea Kayak Shetland is a local tour company that offers tailored trips to suit the ability of participants. They do full-day, half-day and evening tours with a local, experienced guide to ensure you see the best sights safely.

You can find out more about these tours via their website or follow them on Instagram @seakayakshetland.

Sea cave at Westerwick. Photo: Sea Kayak Shetland.

L-r: Westerwick; Westerwick & Ronas Voe. Photos: Sea Kayak Shetland.

Why does Shetland have so many sea caves? This is down to the diversity of geology and how the islands have been exposed to weather and sea action over millions of years. Any small crack or fissure in a rock face will be exploited by the power of the sea and cracks will open up in the rock face, over time these will grow and become caves. Repeated wave action and the compression of air in rock crevices will eventually form a cave – this process does not happen overnight, and it may take thousands of years for a cave to grow! Caves occur more commonly in areas where layers of harder rock sit on top of layers of softer rock – the soft rock will erode more quickly, leaving caves and arches.