Harbour Authority

The Sizewell C (Nuclear Generating Station) Order 2022, requires Sizewell C Limited to first establish, and subsequently act as, the legal regulator and operator of the Sizewell C Harbour Authority.

Our primary responsibilities relate to the safety of vessels and people, efficient navigation within the harbour and the protection of the harbour estate environment and infrastructure.
Specifically, our requirements are to:

  • Comply with the Port Marine Safety Code (PMSC);
  • Ensure safe and efficient port marine operations that help to maintain safety of navigation;
  • Conserve the harbour so that it is fit for use, including providing users with adequate information about conditions in the harbour;
  • Act as a Local Lighthouse Authority (LLA) and to provide and maintain Aids to Navigation ;
  • Report various activities and or incidents to regulators such as the Marine Management Organisation (MMO), Trinity House (General
    Lighthouse Authority), United Kingdom Hydrographic Office (UKHO) and the Maritime & Coastguard Agency (MCA).

Harbour Limits

The Statutory Harbour limits extends to an area approximately 2.2 nautical miles off the Suffolk Coastline adjacent to the Sizewell C Site.
The limits of the harbour area are bounded by an imaginary line commencing at the shore north of the authorised development at 52°14’0’’, 1° 37’ 37’’, then extending in a straight line to a point at 52°14’0’’, 1° 41’ 0’’, then extending in a straight line to a point at 52° 12’ 0’’, 1° 41’ 0’’, then extending in a straight line due west to the coast to a point at 52° 12’ 0’’, 1° 37’ 20.8, then following the level of Highest Astronomical Tide (HAT) to the point at 52°14’0’’, 1° 37’ 37’’.

Chart 1543 shows the extent of the Sizewell C Harbour Authority area.

Notices to Mariners

Please refer to this website for information contained in Notices to Mariners relevant to port marine operations within the SZC harbour area.

VIEW NtoM 1 of 2024_SZC_Establishment of the Sizewell C Harbour Authority (not active)


VIEW NtoM 2 of 2024_SZC_Survey Operations (not active)


VIEW NtoM 3 of 2024_SZC_Water Sampling Operations (not active)


VIEW NtoM 4 of 2024 SZC Survey Operations (not active)


VIEW NtoM 4 of 2024 Update SZC Survey Operations (not active)


VIEW NtoM 4.1 of 2024 2nd Update SZC Survey Operations (not active)


VIEW NtoM 5 of 2024 SZC WaveRider Service (not active)


VIEW NtoM 6 of 2024 Survey Operations (not active)


VIEW NtoM 7 of 2024 Geotechnical Investigations and Seabed Sampling (active)


VIEW NtoM 8 of 2024 Tidal Gauge Service (not active)


VIEW Sizewell C Notice to Mariners No 7 of 2024 (updated) (active)


VIEW Sizewell C Notice to Mariners No 6.1 2024 (not active)


VIEW Sizewell C Notice to Mariners No 6.1 2024 (updated) (not active)


VIEW Sizewell C Notice to Mariners No 8 of 2024 (updated) (not active)


VIEW Sizewell C Notice to Mariners No 9 of 2024 (not active)


VIEW Sizewell C Notice to Mariners No 10 of 2024 (not active)


VIEW Sizewell C Notice to Mariners No 11 of 2024 Survey Operations (not active)


VIEW Sizewell C Notice to Mariners No 11.1 of 2024 Survey Operations (not active)


VIEW Sizewell C Notice to Mariners No 12 of 2024 Dive Operations (not active)


VIEW Sizewell C Notice to Mariners No 14 of 2024 Aid to Navigation Casualty (not active)



VIEW Sizewell C Notice to Mariners No 15 of 2024 Charted Depths and Bathymetry (active)


VIEW Sizewell C Notice to Mariners No 13 of 2024 Sea Water Sampling (not active)


VIEW Sizewell C Notice to Mariners No 16 Buoy (not active)


VIEW Sizewell C Notice to Mariners No 17 Wave Rider Buoy (not active)


VIEW Sizewell C Notice to Mariners No 18 Aid to Navigation Casualty Repair (not active)


VIEW Sizewell C Notice to Mariners No 19 Establishment of the Sizewell C Harbour Authority (active)


VIEW Sizewell C Notice to Mariners No 20 Aid to Navigation Repair (not active)


Marine Safety Plan 2024 – 2025

SZC Harbour Authority has committed to comply with the requirements of the Port Marine Safety Code (PMSC), which includes the publication of a Marine Safety Plan.  This marine safety plan is one component of a comprehensive Marine Safety Management System and serves to support the continuing improvement of all aspects of SZC marine safety performance, and ongoing compliance with the PMSC.

The plan is intended to cover a rolling three-year period but will be refreshed and checked for continuing relevance on an more frequent basis.

For any enquiries, please contact the Harbour Master via email: harbour.master@sizewellC.com

Date: October 2024