Ironman 70.3

Welcome to BT.

A little more context would be helpful towards answering your question. 

Assume you are swimming front crawl. 

what is your current and goal pace?

Ill have a few more questions after you provide this information. 

The 15 yard pool at the local wellness center was the only indoor public pool for about 50 miles of where I lived from 2015-2021.  I did a lot of laps.  It got the job done.  I do fine in open water swims.  Most of my races have been on smooth lakes.  Those are the ones when people are cruising by me.    When the water is rough I seem to be at a slight advantage.  It seems that I get passed by a lot less people in rough water.  In those conditions I just focus on spitting out as much water as a take in, and on maintaining the same form in the open water as I have spend hours and hours practicing in the pool. 

Swimming in shorter pools just means more laps.  While others were doing something like 25m repeats, I was doing 30 yard repeats.  When others were doing 100m repeats, I was doing 120 yard repeats. etc.  For swim training you don't need to do long continue swims to improve.  With swimming form is king.  If you are doing long continuous swims you get fatigued and your form breaks down.  If you are training with poor form you are going to race with poor form.  The recommendation for swimming is to do swim set with short break between then so that you can maintain good form for the entire workout.  Start with swim sets that take about 20-30 minute to complete then added 3-5 minutes or swim time per session every week until you are about to complete 1-1/2 to 2 times your race distance (i.e. 3,000-4,000m).  My fast friends can do 4,000m in an hours.  I am more like 3,000 in an hour.  My workouts have been up to about an hours the past two years, but I have only been doing sprints in that time.  The has been a good swim time for me.  I would like to increase it though.  Especially if I do another 70.3.  I do not come from a swim background.  I am a master athlete and getting closer to 50.          

Good advice from Curtis above.  I'll add that I swim in a 15-yard pool when I travel for work and I can get decent ones in.  It will force you to do some things that go against pool swim coaches, like open turns and no underwaters.  In a longer pool it's fine to do those but if you do a 5-yard underwater dolphin kick off a flip turn you'll only get a couple of strokes each length.  Also those pools are usually pretty shallow.

As for open water, in rough conditions it's tough for everyone and I've lucked out with good conditions on lakes/ponds in my races.