Marine licensing jurisdiction
Guidance on where marine licensing applies and what the key terms mean.
Where marine licensing applies
The Marine Management Organisation (MMO) is responsible for marine licensing in:
- English inshore and offshore waters
- Northern Ireland offshore waters
The MMO is also responsible for certain activities carried out by British vessels, aircraft or structures anywhere in the world.
Marine licensing can apply in tidal rivers, estuaries, near the coast, or out at sea. This guidance explains what we mean by ‘the sea’ and how tidal limits are defined.
You can check if you need a marine licence before you apply.
English waters
English waters include:
- inshore waters – the sea within 12 nautical miles of the English coastline (the territorial limit)
- offshore waters – the sea beyond the territorial limit but within the English Exclusive Economic Zone (EEZ) and the UK sector of the continental shelf, up to 200 nautical miles from the coast
English waters do not include waters belonging to Northern Ireland, Scotland or Wales.
Northern Ireland offshore waters
Northern Ireland offshore waters are the sea beyond 12 nautical miles from the Northern Ireland coastline.
This area is designated as the Northern Ireland Exclusive Economic Zone (EEZ) and forms part of the UK sector of the continental shelf.
These waters do not include waters belonging to Scotland, Wales or England.
What we mean by the sea
For marine licensing, ‘the sea’ means any area submerged at Mean High Water Springs (MHWS). It also includes:
- estuaries, rivers and channels where the tide flows at MHWS up to the Normal Tidal Limit
- enclosed waters, such as docks, where seawater can flow in or out, either permanently or occasionally, for example through a lock
In or over the sea, on or under the seabed
Marine licensing defines locations as:
- in the sea – any location within a relevant body of water
- over the sea – directly above or overhanging the sea, such as a bridge or cantilever
- on the seabed – the ground under the sea, including anything resting on it, such as a shipwreck
- under the seabed – below the surface of the seabed, such as pipelines or cables that are buried
Tidal limits
Mean High Water Springs (MHWS)
Spring tides are when the tidal range is at its highest. Mean High Water Springs is the average of 2 successive high waters during spring tides in each month.
If you do not have specialist equipment, you should treat an area as being below MHWS if:
- it is made wet by the normal ebb and flow of the tide
- there is evidence such as markings or growth that show the tide has reached that point in the past
If you’re unsure, you should get an independent survey to confirm the position.
Normal Tidal Limit
The Normal Tidal Limit is the point in a river, estuary or channel up to which the tide normally flows. This may include areas controlled by locks.