Great Bay 5K Stratham, NH   Oct 25, 2025

The Great Bay 5K is the final race in the popular Seacoast Road Race Series and supports the non-profit Great Bay Stewards. The course passes the shores of Great Bay, and is a fun, fast, scenic, and mostly downhill event.

The accompanying Great Bay 55K Challenge represents the distance of a route around Great Bay; participants can complete the mileage in a day or do it in segments, logging miles in as many days as needed between October 1 and October 25.

All proceeds from the Great Bay 5K and 55K go to the non-profit Great Bay Stewards, which supports conservation, education, community outreach, stewardship, and research of the Great Bay estuary.