Mudlarking on the Thames in London
Last updated: 17 October 2026
Mudlarking — searching the Thames foreshore in London for the objects the tide uncovers — is one of the richest and most tightly-regulated kinds of searching in the country, and its rules are completely different from the rest of the coast. The one thing to understand first: the tidal Thames is not free Crown Estate foreshore. You need a permit from the Port of London Authority to search it — even by eye — and you cannot simply turn up and dig. Permits are limited and demand is very high, so getting one is far from guaranteed, and a guided tour is often the realistic way to experience it. Here's how it actually works.
In short
- Mudlarking is searching the tidal Thames foreshore through London — and it has its own rules.
- The Thames is not the free Crown Estate foreshore: it's managed by the Port of London Authority (PLA).
- You need a PLA foreshore permit to search it — including searching by eye, not just digging.
- Permits are limited and demand is very high, so one may not be available — check the PLA for the current position.
- A guided tour (such as those the PLA recommends) is the realistic way to try mudlarking without a permit.
- The Treasure Act applies, and finds are recorded with the Portable Antiquities Scheme through a London Finds Liaison Officer.
- This is not the same as beach detecting on the open coast — don't apply the Thames rules to a seaside beach, or the other way round.
What is mudlarking?
Mudlarking is the searching of the Thames foreshore — the mud, sand and shingle exposed at low tide — for the objects London has dropped, lost and thrown into the river over two thousand years. The tidal river is an extraordinary preserver: its anaerobic mud protects leather, wood, pottery and metal that would have rotted or corroded away elsewhere, so the foreshore turns up everything from Roman coins and medieval pilgrim badges to clay pipes and Tudor pins. Most of the best finds are lying on the surface, revealed by the last tide, which is why eyes and patience matter more than a spade.
The key rule: the Thames is not free foreshore
This is the point almost everyone gets wrong. On much of the open coast, the Crown Estate's foreshore can be searched without a formal permit. The tidal Thames is different. It is managed by the Port of London Authority, not the Crown Estate's permissive arrangement, and the PLA requires a foreshore permit for any searching of the foreshore — including searching by eye, not only digging or metal detecting. There is no "right to roam and search" on the Thames foreshore: without a permit, mudlarking there isn't allowed, however it's done.
Permits: the current position
The PLA runs a Thames foreshore permit scheme, and the permit is what makes mudlarking lawful. The number of permits is capped, and demand has far outstripped supply, so you should not assume you can simply apply and start — at different times the scheme, and any waiting list, may be open or closed.
Because that position changes, we don't quote a fee or an application status here on purpose — both move. The PLA's Thames foreshore permits page is the single source for the current rules, any fee, and whether permits or a waiting list are open right now. Check it before you plan anything — it's the only place that's authoritative on the day.
If you want to try mudlarking in the meantime, the realistic route is a guided foreshore tour led by an accredited guide — the PLA itself points visitors to registered tours for a one-off experience, which also leaves permits for people who mudlark regularly.
Finds, treasure and the FLO
The rules on what you find are the same in spirit as anywhere else in England. The Treasure Act applies: a find that meets the treasure definition must be reported to the coroner within 14 days. Other finds are recorded, as elsewhere, with the Portable Antiquities Scheme — the Thames has its own dedicated recording through a London-based Finds Liaison Officer, and foreshore finds are an important part of the national record. Recording is free and you keep your finds; our guides to Finds Liaison Officers and the PAS and the metal detecting laws in England cover both. As ever, don't clean anything that might be important — the Thames's preservation is part of what makes a find special.
Mudlarking vs beach detecting
It's worth keeping the two apart, because people often confuse them. Mudlarking is the tidal Thames foreshore, PLA-permit-gated, mostly surface searching in central London. Beach detecting on the open coast is a different world: much of that foreshore is Crown Estate land you can search without a formal permit, the finds are different, and the timing is driven by storms and spring tides rather than a permit. If you're heading for the seaside, our guide to beach metal detecting in England is the one you want — the Thames rules on this page don't apply there.
That split runs through Muld too. Its beach conditions read the open coast — the wind and waves that scour a beach — and the Thames has its own tide-based tool in Muld+, built around the low-tide windows and foreshore timing that make a mudlarking session. The two are kept apart on purpose, because the river runs on the tide and the coast runs on the storms. What Muld can't do is grant you a permit — that stays the Port of London Authority's to give.
Keep a record of what the river gives up
Wherever you search, a good record is worth keeping. Muld is a private find journal on your own phone — photograph each find, note where it came from, and keep it ready for your Finds Liaison Officer. Nothing leaves your phone unless you choose to share it. Muld doesn't grant permits or report to the Portable Antiquities Scheme for you — it's your own field record. The core app is free.
Common questions
Do you need a permit to go mudlarking on the Thames?
Yes. The tidal Thames foreshore is managed by the Port of London Authority, not the Crown Estate, and the PLA requires a foreshore permit to search it — including searching by eye, not just digging. Without a permit, mudlarking on the Thames isn't allowed. Check the PLA's Thames foreshore permits page for the current rules and whether permits are available.
Can I get a Thames mudlarking permit right now?
It depends on the current position, which changes. Permits are capped and demand far outstrips supply, so you may not be able to apply immediately — the scheme and any waiting list can be open or closed at different times. The PLA's Thames foreshore permits page is the single source for whether the scheme is open, the rules and any fee. Until a permit is available, a guided foreshore tour is the realistic way to experience mudlarking.
Is mudlarking on the Thames the same as beach detecting?
No. Mudlarking is the tidal Thames foreshore, which needs a Port of London Authority permit and is mostly surface searching. Beach detecting on the open coast is different: much of that foreshore is Crown Estate land you can search without a formal permit, and the timing is driven by storms and tides. Don't apply the Thames permit rules to a seaside beach, or the open-coast rules to the Thames.
Can I use a metal detector while mudlarking?
Only under the terms of a PLA foreshore permit, which sets out what is and isn't allowed — different permit types cover searching by eye and the use of tools such as detectors, and there are restricted areas. Much mudlarking is surface searching by eye in any case. Always work within your permit's conditions, and check the PLA page for the current rules.
What do you do with mudlarking finds?
Anything that might be treasure must be reported to the coroner within 14 days, in practice through a Finds Liaison Officer. Other finds are recorded, voluntarily and for free, with the Portable Antiquities Scheme — the Thames has dedicated recording through a London FLO — and you keep your finds. Don't clean anything old or important; the river's preservation is part of what makes a find valuable.
Where can I go mudlarking without a permit?
On the tidal Thames, you can't search without a permit — but you can join a guided foreshore tour led by an accredited guide, which is the route the PLA points visitors to for a one-off experience. Elsewhere in the country, searching the open-coast foreshore is a different activity with different rules; see our beach metal detecting guide.
Official sources
Permit rules and availability on the Thames change, so the PLA's own page is the source that matters — always check it before relying on anything here.
- Port of London Authority — Thames foreshore permits The permit scheme, the current rules and availability, and any fee — the single source of truth for the Thames foreshore.
- Portable Antiquities Scheme — find your Finds Liaison Officer Recording Thames foreshore finds, through a London-based FLO.
- GOV.UK — Treasure The duty to report treasure within 14 days, which applies on the foreshore as inland.