Seaham put-in

Seaham's harbour was built in 1828 by the 3rd Marquess of Londonderry and later extended, reopening in 1905 with an unusual design of interconnecting locks rather than the more common two-wall construction. The North Dock, where the slipway sits, was redeveloped as a leisure marina in phases completed by Durham County Council; the final phase, in 2013, installed floating pontoons for 77 leisure craft, reinstated the dock gates and refurbished the slipway. The marina, now run as a not-for-profit Community Interest Company, has 96 pontoon berths in total.

South of the harbour the coast is part of the Durham Coast Site of Special Scientific Interest and Special Area of Conservation, the only example in the UK of vegetated sea cliffs on magnesian limestone, running for over 20km from South Shields to Blackhall Rocks. These beaches, including Blast Beach immediately south at Dawdon, were reshaped by colliery spoil tipped directly onto the shore until the mines closed; a 1997 to 2002 clearance project removed 1.3 million tonnes of spoil and reclaimed 80 hectares of land, and natural erosion continues to return the beaches toward their earlier profile.