Do I Need an MMO Marine Licence?
If you're planning work in, over or under the sea, you've probably heard someone mention an MMO Marine Licence.
It's one of the questions we're asked most often.
"We're only replacing a pontoon. Do we need one?"
"It's just repair work, surely we don't need another consent?"
"We've already got planning permission – doesn't that cover it?"
The answer is... it depends.
Every marine project is different, but one thing is certain: understanding whether you need a Marine Licence early in the project can save weeks, or even months, of delay later.
At TILT Engineering & Design, we regularly help clients navigate the marine licensing process, whether that's supporting a simple repair project or coordinating technical information for major waterfront developments. In this guide we'll explain what an MMO Marine Licence is, when it's likely to be required and how to avoid some of the common pitfalls.
What is an MMO Marine Licence?
The Marine Management Organisation (MMO) is responsible for licensing many activities carried out in UK marine waters.
The purpose of the licence isn't simply to create paperwork. It's there to ensure that works carried out in the marine environment don't have an unacceptable impact on navigation, wildlife, water quality, coastal processes or other users of the sea.
If your project involves placing, removing or altering structures below Mean High Water Springs, there's a reasonable chance a Marine Licence will be required.
The exact requirements depend on the type of work, where it's taking place and whether any exemptions apply.
What types of work usually require a Marine Licence?
The list is surprisingly broad.
Projects that commonly require a Marine Licence include:
Construction of new pontoons and marinas
Quay wall construction and repairs
River wall repairs
Slipways and boat ramps
Jetty construction
Berthing dolphins
Piling works
Dredging
Installation of pipelines or cables
Beach recharge and coastal defence works
Removal of existing marine structures
Temporary construction platforms
Outfalls and intake structures
Even relatively small maintenance projects may require consent depending on the location and nature of the works.
That's why it's always worth checking before committing to a programme.
Doesn't planning permission cover this?
This is probably the biggest misconception we come across.
Planning permission and a Marine Licence are completely separate approvals.
Planning permission considers whether a development is acceptable from a planning perspective.
A Marine Licence looks specifically at the impacts of carrying out works within the marine environment.
On many projects you'll need both.
Depending on the location, you may also require:
Port of London Authority River Works Licence
Environment Agency approvals
Flood Risk Activity Permit
Listed Building Consent
Harbour Authority approvals
Environmental permits
Each organisation has its own responsibilities, and obtaining one approval doesn't automatically satisfy another.
Are there any exemptions?
Yes, but they're often misunderstood.
Certain maintenance activities and low-risk works may fall within Marine Licensing Exemptions.
However, exemptions depend on very specific criteria.
For example:
the type of work
where it's taking place
the construction method
the materials being used
whether environmental impacts are likely
We've occasionally spoken to clients who assumed their project was exempt because it was "only a repair". After reviewing the scope, it became clear that a licence was still required.
It's always better to confirm early than discover the issue once contractors are ready to start.
What information does the MMO need?
People often think applying for a Marine Licence is simply filling in an application form.
In reality, the quality of the supporting information usually determines how smoothly the application progresses.
Depending on the project, you may need:
Location plans
Engineering drawings
Construction methodology
Environmental information
Habitat surveys
Water Framework Directive assessments
Programme of works
Risk assessments
Navigation considerations
Supporting engineering calculations
The aim is to demonstrate exactly what you're proposing, how it will be carried out and what steps have been taken to minimise environmental impacts.
A well-prepared application gives regulators confidence and usually results in fewer technical queries later.
Why do Marine Licence applications get delayed?
In our experience, delays rarely happen because the regulator wants to slow projects down.
More often, it's because information is incomplete.
Some of the most common issues include:
Engineering drawings changing after submission.
Environmental surveys being commissioned too late.
Construction methods not being fully developed.
Missing technical information.
Applications submitted without considering other required consents.
We've found that investing a little more time before submitting an application nearly always saves time during the approval process.
How long does an MMO Marine Licence take?
There's no fixed answer because every project is different.
A straightforward maintenance project is naturally much quicker to assess than a large waterfront development involving multiple stakeholders and environmental considerations.
If consultation with other organisations is required, or additional information is requested during the process, timescales can increase.
Our advice is always to factor licensing into the programme as early as possible.
It's far easier to adjust a programme at the planning stage than explain delays once contractors have been appointed.
How can engineering help the licensing process?
Good engineering doesn't just make construction easier.
It often makes licensing easier too.
Clear drawings, practical construction methods and a well-thought-out design help demonstrate that a project has been properly considered.
At TILT we regularly support clients by:
Preparing engineering drawings
Developing construction methodologies
Providing marine engineering advice
Coordinating technical information
Responding to regulator queries
Supporting Marine Licence applications
Because we're involved in both engineering and consenting, we can often identify potential issues before they become delays.
Frequently Asked Questions
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No. Some activities are exempt, but exemptions are very specific. If you're unsure, it's worth checking before work begins.
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Application fees vary depending on the type and scale of the project. Additional costs may also include engineering design, environmental surveys and specialist assessments.
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No. Works that require a Marine Licence should not begin until the licence has been granted.
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Sometimes. The fact that work is classed as a repair doesn't automatically make it exempt.
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Yes. We regularly support clients by preparing engineering drawings, technical information and coordinating the documents required for Marine Licence applications.
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As early as possible. Marine licensing should be considered during the initial planning stages of a project, not once construction is ready to begin.
Planning marine works?
Whether you're repairing an existing quay wall, installing a new pontoon or delivering a larger waterfront development, understanding the licensing requirements at the start of the project can save significant time and cost later.
At TILT Engineering & Design, we provide practical marine engineering advice alongside specialist support for Marine Licence applications, helping clients move projects from concept through to construction with confidence.
If you're unsure whether your project needs an MMO Marine Licence, we're always happy to have an informal conversation.