Yay! It was distance day. For the main set, add 100 yards to the longer distances with each round. It’s a long main set, but you get a decent amount of yards for 55 minutes.
As ever, adjust intervals, distances, and even strokes for what works for you.
55-minute swim workout, distance workout
500 warmup (~7:25 min)
Warmup set (600 yds, 9:40 min)
4 x 150 on 2:25
Main set (2100 yds, 32 min)
Set 1 3x (2100 yds, 32 min)
200 on 3:00
300/400/500 on 4:30/6:00/7:30
100 on 1:40—active recovery
Only the longer distance in the middle changes per set
Bonus set (100 yds, 2 min)
4 x 25 sprint on :30
150 warm down
Total yards: 3450