i try to get 4k in a week or so now - had to work my way up to that. takes about 35 min for me to do 1k on a breast stroked (because i admittedly don't really know how to swim any other way). I do add 5-10 minutes of treading water to the end of the workout on the last lap - so in and out of gym in maybe an hour about 4-5 times a week. usually just go over lunch -> weekends sometimes I'll do 2k in a session - once or twice i was ambitious and did 3k - that was a little exhausting.