Go to Cefn Sidan (unless you are boating), Burry Port & North Channel are the home of the crab, unless you fish a big bait (whole razor or clam or mackerel fillet) you wil get "cleaned" in minutes!
Fish Cefn Sidan from low water up to the top & 1 hr over using lug/rag & use flourescent yellow beads as an attractant.
As Blueskip says-fish Cefn Sidan-tried Burry Port last week and didn't have a bite although Cefn hasn't been that hot this week, there's been no surf. If you need directions search for threads and I'm sure I put them up somewhere-if you have no joy ask and i'll re-post; and Skip's right about the attractors
Llangenith Beach is a good mark, but you need to fish it on small tides & at night, otherwise you catch mainly surfers & nothing else!, baits razor/lug or a big lug bait 2/4 up the line or a 2/0 pennel rig.