Port of Fosdyke sits on the River Welland near its mouth at The Wash, in the Lincolnshire village of Fosdyke. The site has served as a port since at least medieval times, when it functioned as a trading hub for Boston and the surrounding region.

Commercial activity continued into the modern era, with small coasters once navigating the Welland as far as Spalding.

Following the decline of commercial trade, the former wharves were redeveloped under the Port of Fosdyke Act 1987, and the site is now Fosdyke Yacht Haven — a pleasure boat marina and boatyard.

The original quay remains, and the facility includes dry dock services for sailing craft. A fixed road bridge with 5-metre headroom now spans the river at this point, replacing the earlier swing bridge.