Crymlyn Bog

Crymlyn Bog is a nature reserve featuring lowland fen habitat with extensive reed beds, sedge meadows, and willow scrub on waterlogged ground near Swansea. The site covers a substantial area of wetland vegetation shaped by seasonal water levels and natural drainage patterns.

The wetland developed in a valley shaped by ancient river activity during earlier inter-glacial periods when the Clydach and Neath rivers flowed through the area. This geological foundation created the conditions for the fen ecosystem that exists today.

Scientists and researchers regularly visit the reserve to study and document the rare plant species and monitor the population of the fen raft spider.

Visitors can walk through the reserve on designated boardwalk trails that keep you above the wet ground. The main path takes about 45 minutes to complete and suits most fitness levels.

The reserve is home to one of only three populations of the fen raft spider in the whole country. This rare spider indicates the site maintains excellent conditions for specialized species.

GPS coordinates: 51.63640,-3.88833

Latest update: December 13, 2025 12:20