Facts and figures about Scotland's sea area (coastline length, sea area in sq kms)

Data Type: 

How long is the coastline of Scotland?

We estimate Scotland’s coastline to be 18,743 km in length along the high water line (“mean high water spring” or MHWS)

Coastlines are difficult to measure accurately because of the coastline paradox.  All published figures are estimated, and will vary depending on the size of the ruler used to measure (the scale of the map). 

Source: Ordnance Survey Boundary-Line


How big are Scotland’s seas?

We estimate the area of Scotland’s seas to be 462,315 km2 using the definition of the “Scottish zone” in the Scotland Act 1998 (see table below for other definitions).  Scotland’s seas are nearly six times larger than the land area of Scotland.

The figure above reflects the UK Exclusive Economic Zone (EEZ) adjacent to Scotland, which accounts for 63% of the UK EEZ.

​The area of sea can vary depending on the map projection and coastline scale used for the calculations. A more detailed coastline can introduce variations and additional islands and skerries.

Sources: UKHO Maritime Limits | SEPA Transitional and Coastal Water Bodies | JNCC MPA Statistics.


How many islands does Scotland have?

We estimate Scotland to have over 900 islands, of which 118 are inhabited.

The most remote Scottish island is Rockall, which is around 300 km from Hirta (Hiort) in the St Kilda archipelago.

Source: National Records of Scotland (NRS)


Which part of Scotland is furthest from the sea?

We estimate the furthest point from the sea to be Glen Quoich near Braemar, which is around 65 km from the sea.

Source: Ordnance Survey Open Names.


How deep are Scotland’s seas?

The deepest point in the Scottish zone is the Rockall Trough, with a depth of around 2,500m

On the extended continental shelf beyond Rockall, the deepest point in the Scottish offshore region is over 3,000 m deep.  (For comparison, the summit of Ben Nevis is 1,345 m above sea level.)

The average depth of the Scottish zone is around 600 m below sea level, or nearly 1 km (903 m) including the continental shelf limits.

Source: EMODnet 1/16 ArcMinute DEM  


How many Marine Protected Areas are in Scotland? How much of Scottish seas are covered by Marine Protected Areas?

As of March 2022, there are 233 sites for nature conservation covering 228,118 km2 or 37% of the continental shelf area adjacent to Scotland. Sites can have overlapping designations. 

  • 58 Special Areas of Conservation (SACs) for European protected species and habitats. 
  • 58 Special Protection Areas (SPAs) for birds.
  • 36 Nature Conservation Marine Protected Areas for marine species, habitats, and geological features.
  • 16 Ramsar sites for wetlands of international importance.
  • 65 Sites of Special Scientific Interest (SSSIs) for species, habitats, and geological features.

These figure does not include other types of MPA such as Historic MPAs, Demonstration & Research MPAs, or marine management areas such as fisheries-specific restrictions.

Source: JNCC and Scottish Government


How long are Scotland’s rivers and streams?

Scotland has more than 125,000 km of rivers and streams varying from small highland burns to deep, wide lowland rivers such as the Tay.

There is also a 220 km canal network in Scotland.

There are over 25,500 lochs in Scotland, with the Western Isles and Sutherland having the highest concentration of lochs.

Source: SEPA


Table 1: Sea areas of the waters adjacent to Scotland, by United Nations Convention on the Law of the Sea definitions

Illustrative Map Landward Boundary Seaward Boundary Description Area (km2)
Illustrative map of the intertidal area around Scotland
Mean High Water Spring (MHWS) Mean Low Water Spring (MLWS)
  • Intertidal area
Internal waters adjacent to Scotland
MHWS Baseline of the Territorial Sea (TS) 34,920
Coastal and transitional waters (3NM) adjacent to Scotland
MHWS 3NM from baseline 48,710
Inshore waters (6NM) adjacent to Scotland
MHWS 6NM from baseline 62,212
The territorial sea (12NM) limit adjacent to Scotland
MHWS Territorial Sea Limit (up to 12NM from baseline) 90,400
The Exclusive Economic Zone (EEZ) adjacent to Scotland
MHWS Exclusive Economic Zone Limit (up to 200NM from baseline) 462,315
The Continental Shelf limits adjacent to Scotland
MHWS Continental Shelf Limits (up to 350NM from baseline) 617,643
Territorial sea, outside internal waters, adjacent to Scotland
Baseline Territorial Sea Limit 55,480
The exclusive economic zone, outside territorial sea, adjacent to Scotland
Territorial Sea Limit Exclusive Economic Zone Limit 371,915
The continental shelf limits, outside territorial sea, adjacent to Scotland
Territorial Sea Limit Continental Shelf Limits 527,243
The Special Area agreed between the UK and Kingdom of Denmark on behalf of the Faroe Islands
Schedule B of the The Exclusive Economic Zone Order 2013 Schedule A of the The Exclusive Economic Zone Order 2013 8,014

NM = nautical mile


Table 2: Sea area, coastlines and depths of the Scottish Marine Regions and Offshore Marine Regions (to Continental Shelf Limits)

Scottish Marine Area Region Area (km2) Distance along MHWS (km)* Deepest Point (m) Shallowest Point (m) Average Depth (m)
Forth and Tay Inshore 4,487 775 97 MHWS 39
North East Inshore 3,153 307 224 MHWS 63
Moray Firth Inshore 5,876 985 256 MHWS 50
Orkney Islands Inshore 9,256 1,228 195 MHWS 65
Shetland Isles Inshore 12,309 2,382 188 MHWS 93
North Coast Inshore 2,443 544 124 MHWS 68
West Highlands Inshore 10,420 3,656 322 MHWS 82
Outer Hebrides Inshore 20,848 3,915 268 MHWS 88
Argyll Inshore 12,044 2,918 320 MHWS 66
Clyde Inshore 4,279 1,256 198 MHWS 58
Solway Inshore 3,724 777 314 MHWS 52
Long Forties Offshore 34,508 n/a 178 32 80
Fladen and Moray Firth Offshore Offshore 40,261 n/a 248 35 111
East Shetland Shelf Offshore 33,713 n/a 175 58 128
North and West Shetland Shelf Offshore 28,676 n/a 623 72 254
Faroe Shetland Channel Offshore 42,752 n/a 2,418 343 1,304
North Scotland Shelf Offshore 28,820 n/a 1,073 15 213
Hebrides Shelf Offshore 30,437 n/a 1,359 19 241
Bailey Offshore 74,797 n/a 2,360 322 1,365
Hatton Offshore 155,215 n/a 3,185 158 1,783
Rockall ** Offshore  59,625 # 2,576 MHWS 1,386
Total   617,643 18,743 3,185 MHWS 903
Scottish Zone for comparison   462,315 18,743 2,576 MHWS 611

* Derived from OS Boundary-Line and subject to the coastline paradox

** The Rockall assessment area also includes the inshore area within the territorial sea. The territorial sea around Rockall is part of the “Scottish inshore region” under the Marine and Coastal Access Act 2009, but is not defined as a Scottish Marine Region in the The Scottish Marine Regions Order 2015.

# The coastline of Rockall is not mapped at a suitable scale

Sources: OceanWise 1 ArcSecond DEM | EMODnet 1/16 ArcMinute DEM  | Ordnance Survey Boundary-Line | UKHO Maritime Limits


Table 3: Sea areas of UK Countries and Crown Dependencies

Description Area (km2) Approx. %
Scottish zone 462,315 63%
English zone 230,190 32%
Welsh zone 30,778 4%
Northern Irish zone 6,819 1%
UK Exclusive Economic Zone (Total) 730,102 100%
Isle of Man territorial waters 3,976  
Guernsey territorial waters 3,691  
Jersey territorial waters 2,965  

Source: UKHO Maritime Limits