How prominent is Bioda Mor?

Bioda Mor's prominence is its full height — 179m — 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 Bioda Mor?

The standard good-weather months for Bioda Mor 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 Bioda Mor?

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

By the OutdoorSCOT editor

Photo: David Dixon / CC BY-SA 2.0 via Geograph

Submit a photo

Marilyn · Outer Hebrides

Bioda Mor

Bioda Mor — 'the big point' — rises in the NF 104 grid square at the south-west end of Dùn, the cliffed islet that shelters Hirta's Village Bay in the St Kilda group. The 178m summit caps a dramatic narrow ridge above sheer cliffs.

Gaelic: “big” · Pronunciation: bioda more

Quick facts

Height: 178.5m/ 586ft
Prominence: 179 m
Difficulty: 1 / 5Easy
Grid ref: NF 10427 97348
Dogs: Dogs on lead required near livestockDog-friendly guide ↗

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

No GPX track yet

Walked this route? Share your track to help other walkers.

Submit your GPX

Standard route

maritime grassland 55% · rocky ridge 30% · cliff edges 15%

GPX needed

Elevation profile coming with the GPX track

Dùn is separated from Hirta by a narrow channel and can only be landed on by small boat in calm seas; do not attempt to cross on foot. Access to the St Kilda islands is managed by the National Trust for Scotland — check with NTS before planning a landing. Once ashore, a steep grass scramble follows the spine of Dùn.

Terrain

Steeply tilted maritime grass over gabbro bedrock, with vertical drops on both sides of the ridge. Puffin burrows riddle the turf in summer and demand careful foot placement.

In winter

No winter access — the crossing from Hirta is barely possible even in calm summer conditions, let alone with autumn or winter swell running.

Kit for this: the winter Munro kit list · which boots take crampons

Outside the SAIS network. No Scottish Avalanche Information Service forecast covers Bioda Mor. 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 14m
Edinburgh15h 42m

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

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. There is no bothy to stay in; the National Trust for Scotland looks after the islands, so check its current guidance on landing and camping before you go.

OS maps: OS Landranger 18, OS Explorer 460W

Mobile signal: None. St Kilda; no signal of any kind. Charter boat and satellite communications only.

Current conditions

Daylight Today

10h 44mwalking daylight

Sunrise: 07:38
Sunset: 16:59
Civil dawn: 06:56
Civil dusk: 17:40

NOAA Solar Calculator · 28 October 2026

Got a photo of Bioda Mor?

30 seconds, helps other walkers.

Submit a photo

Walked it with a GPX?

From your watch or phone.

Submit GPX

Trip report?

Share what it was actually like.

Get in touch →

Bioda Mor — common questions

How difficult is Bioda Mor?: Bioda Mor carries a 1/5 (easy) grade on the OutdoorSCOT scale. Terrain: Steeply tilted maritime grass over gabbro bedrock, with vertical drops on both sides of the ridge.
How prominent is Bioda Mor?: Bioda Mor's prominence is its full height — 179m — 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 Bioda Mor?: The standard good-weather months for Bioda Mor 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 Bioda Mor?: On a lead only — the route crosses ground with livestock or nesting-bird interest.
What's mobile reception like on Bioda Mor?: None. St Kilda; no signal of any kind. Charter boat and satellite communications only.
How do I get the ferry to Bioda Mor?: 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. 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. There is no bothy to stay in; the National Trust for Scotland looks after the islands, so check its current guidance on landing and camping before you go.
Is Bioda Mor safe in winter?: No winter access — the crossing from Hirta is barely possible even in calm summer conditions, let alone with autumn or winter swell running.

Get the OutdoorSCOT weekly

One email a week — new route, hill and bothy guides, seasonal conditions and the odd hard-won lesson. No spam, unsubscribe in one click.