hi jean i swim as well and i thought about this as i inject mtx so i actually changed my day so now jag on thurs which works ok, this lets me swim on my normall tues with some friends who i meet every week, works for me.i do put a very good big waterproof plaster on and a little vasaline first for extra water protection if i do go on the same day as mtx sometimes the notion just hits and i'm fine, no one sees whats under the swimsuit,dorothy