We don’t do lots of swimming with fins, but when we do, I like to make sure it is fast.
Here is one way I like to do it:
4-6 rounds of:
100 fast swim with fins, where the goal is to go your lifetime best time, or your goal time, or the team record
100 ez swim free breathing every 3
Total interval around 5 minutes
Provide an incentive for going a best time or breaking a record: maybe coach does pushups, or relays at the end, etc. I have the breaststrokers go flutter kick with the fins on –they end up going really fast that way!