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Guidance

Diving and snorkelling around seagrass and seahorses

What to do during a dive or snorkel in seagrass or a known seahorse location, including when you may need a wildlife licence

Before you dive or snorkel  

Both species of seahorse native to the UK are protected under section 9 of the Wildlife and Countryside Act 1981. These are spiny or long-snouted seahorse and the short-snouted seahorse. Both species are commonly observed in seagrass beds.  

It is an offence to: 

  • Intentionally kill, injure or take a seahorse 

  • Intentionally or recklessly damage, destroy or obstruct access to a structure or place a seahorse uses for shelter or protection. 

  • Intentionally or recklessly disturb a seahorse while it is occupying a structure or place it uses for shelter or protection 

You must have a wildlife licence if you dive or snorkel and intend to do something likely to disturb seahorses. This could include taking photographs or filming. Intentionally disturbing seahorses without a wildlife licence could lead to enforcement action. 

MMO may issue a wildlife licence for specific reasons, including some scientific or educational activities.  

Understand and apply for marine wildlife licences and report an incident]. 

If you encounter a seahorse 

If you encounter a seahorse while swimming, diving or snorkelling: 

  • Do not spend more than five minutes observing it 

  • Never move or touch it 

  • Do not crowd around it with other people  

  • Do not pursue it if it swims away 

  • Retreat slowly to at least 5 metres away if it shows signs of stress, avoiding sudden movement 

  • Keep hoses, gauges and other equipment tucked away 

  • Do not allow your arms, legs or equipment to dangle onto or drag across the seabed 

Signs of stress in a seahorse 

A stressed seahorse may: 

  • Swim away or make erratic movements 

  • Rise into the water column and swim with its tail curled up  

  • Hold its head down toward its chest  

  • Turn its back, curl up, lie flat or move away 

  • Become darker in colour, especially in the squares between its body ridges 

If you see any of these signs, move away slowly and give the seahorse space.  

Photographs and videos 

Images and videos shared publicly should model the actions on this page. MMO may investigate photographs or videos that show a stressed seahorse or suggest that an offence has occurred. This could lead to enforcement action. 

Report a seahorse sighting 

Records of seahorse distribution help their conservation. Report a seahorse seen in the sea or stranded to Natural England at seahorses@naturalengland.org.uk 

Include: 

  • When and where you saw the seahorse 

  • A map location, GPS coordinates, grid reference or What3words location where possible 

  • A photograph where you can take one without causing disturbance 

You can also report sightings to The Seahorse Trust to support its research. 

Seagrass protection and recovery - GOV.UK

Updates to this page

Published 25 September 2026

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