Bac Lava: I love swimming in the estuary here because the scenery changes so much every day. In the summer, as the water is shallow, the sea warms up very quickly.
I often get bemused looks from the walkers and fishermen on the beach, but on a quiet evening with the herons, curlews and oyster-catchers for company and the sun setting over the Lake District hills, the sense of space is wonderfully calming. From the promenade, walk along the beach, past the coast guard station, to the next slipway, and go in on the sandy part to the right of the rocks but bring a bottle of water to splash over your feet as it can get muddy.
Because it's a tidal estuary, be sensible and swim either at low water, when the river current acts like a water treadmill to swim against, or at the turn of high tide as the water goes slack before it turns out to sea.