Swum here several times, most recently in autumn 2022, and have relatives who do regularly. Easy access, ‘Bath Tap public toilets’ (per Google Maps) nearby, cafes further down the prom towards pier. Not a local, so I find it tricky to judge tides/etc, but there’s a local group on Facebook (Felixstowe Swimscapes) that looks active and helpful — seems to swim near Cobbold’s Point. There are groynes to be aware of. Parking can be difficult during the day in good weather as it’s a popular place.