How prominent is Stac an Armin?

Stac an Armin's prominence is its full height — 197m — because it is the highest point of its landmass, with no higher ground connected to it. Marilyns are defined by that measure: at least 150m of drop on all sides.

When should I climb Stac an Armin?

The standard good-weather months for Stac an Armin are March, April, May, June, July, August, September, October. Outside those months, expect winter conditions on the high ground — full mountain kit, navigation skills, and a check of the SAIS avalanche forecast for the relevant region.

Can I bring my dog up Stac an Armin?

On a lead only — the route crosses ground with livestock or nesting-bird interest.

How do I get the ferry to Stac an Armin?

Private charter from Leverburgh (Harris) or Oban. No regular service — chartered day trips and stays May–Sep only, weather dependent in summer; No access in winter in winter. Book at least 90 days ahead. St Kilda is 64km west of the Outer Hebrides — one of the most remote places in Britain. Access by private charter boat (weather permitting) or NTS-arranged visits. Camping and bothy accommodation available; no day trips possible.

By Gary

Photo: Rob Farrow / CC BY-SA 2.0 via Geograph

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Marilyn · Outer Hebrides

Stac an Armin

Stac an Armin, in the NA 151 grid square just north of Boreray, is the tallest sea stack in Britain at 197m. The Marilyn classification masks the reality that this is a vertical rock pillar surrounded by deep Atlantic water and home to a vast colony of gannets and other seabirds.

Quick facts

Height: 197.3m/ 647ft
Prominence: 197 m
Difficulty: 1 / 5Easy
Grid ref: NA 15132 06417
Dogs: Dogs on lead required near livestockDog-friendly guide ↗

Height and prominence cross-checked against the Database of British and Irish Hills (CC BY).

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Standard route

bare rock 80% · seabird colony 20%

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Elevation profile coming with the GPX track

A serious sea-cliff climb rather than a walk. Boats from Harris or Skye drop climbers at the only landing ledge in unusually calm seas, and a roped ascent of grass-mixed rock reaches the small summit. Allow a full day for the attempt.

Terrain

Sheer gabbro and dolerite walls plastered with guano and tussock grass, and ledges crowded with nesting gannets. The rock is mossy and slippery and protection is sparse.

In winter

No winter access whatsoever. The stack is climbable only in flat-calm summer conditions when boats can hold position long enough to put climbers ashore.

Outside the SAIS network. No Scottish Avalanche Information Service forecast covers Stac an Armin. SAIS forecasts six areas only — Northern and Southern Cairngorms, Creag Meagaidh, Lochaber, Glencoe and Torridon — and this hill is outside all of them, so there is no avalanche forecast to read for it. No MWIS mountain forecast covers this area either. In winter, work from a local weather forecast, judge snow stability from first principles, and treat any cornice or wind-loaded slope with extra caution.

Best time of year

Best OK Avoid

Getting there

Glasgow12h 10m
Edinburgh15h 37m

Ferry access

Private charter from Leverburgh (Harris) or Oban

Crossing time180 min
Summer sailingsNo regular service — chartered day trips and stays May–Sep only, weather dependent
Winter sailingsNo access in winter
Book ahead90 days

St Kilda is 64km west of the Outer Hebrides — one of the most remote places in Britain. Access by private charter boat (weather permitting) or NTS-arranged visits. Camping and bothy accommodation available; no day trips possible.

OS maps: OS Landranger 18, OS Explorer 460W

Mobile signal: None. St Kilda sea stack; completely off-grid.

Current conditions

Daylight Today

14h 17mwalking daylight

Sunrise: 07:01
Sunset: 19:58
Civil dawn: 06:21
Civil dusk: 20:38

NOAA Solar Calculator · 14 September 2026

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Stac an Armin — common questions

Is Stac an Armin a hard climb?: Stac an Armin is rated 1/5 (easy) on the OutdoorSCOT scale. Terrain: Sheer gabbro and dolerite walls plastered with guano and tussock grass, and ledges crowded with nesting gannets.
How prominent is Stac an Armin?: Stac an Armin's prominence is its full height — 197m — because it is the highest point of its landmass, with no higher ground connected to it. Marilyns are defined by that measure: at least 150m of drop on all sides.
When should I climb Stac an Armin?: The standard good-weather months for Stac an Armin are March, April, May, June, July, August, September, October. Outside those months, expect winter conditions on the high ground — full mountain kit, navigation skills, and a check of the SAIS avalanche forecast for the relevant region.
Can I bring my dog up Stac an Armin?: On a lead only — the route crosses ground with livestock or nesting-bird interest.
What's mobile reception like on Stac an Armin?: None. St Kilda sea stack; completely off-grid.
How do I get the ferry to Stac an Armin?: Private charter from Leverburgh (Harris) or Oban. No regular service — chartered day trips and stays May–Sep only, weather dependent in summer; No access in winter in winter. Book at least 90 days ahead. St Kilda is 64km west of the Outer Hebrides — one of the most remote places in Britain. Access by private charter boat (weather permitting) or NTS-arranged visits. Camping and bothy accommodation available; no day trips possible.
Is Stac an Armin safe in winter?: No winter access whatsoever. The stack is climbable only in flat-calm summer conditions when boats can hold position long enough to put climbers ashore.

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