The regular visitor took a swim near the village of Llangrove, in what looks to be late at night.
The location is great for mammals due to its stream, rough grassland, meadow and great hedgerows.
The otter is a regular visitor to the stream which is managed by a team of volunteers who are continually improving the habitats for nature.
The trust is the largest membership-based wildlife organisation in the county and managed 55 nature reserves. Around 530 hectares of land reserved for wildlife.