realistic 800m swim time for first tri

Hi Haley, welcome to BT and triathlon

Sure, it's very reasonable with your background to get down to 15:00, especially if you can truly put in a good workout 1-2x/week.

However, is your tri with a pool swim, or lake, or river or ocean? Open-water swimming is a completely, completely different scenario, and likely you will be surrounded by people punching, kicking, clawing (not on purpose--that's just the nature of swimming hard in close quarters with others).

it will be an open water swim, so i know that my time will be a bit slower. i have heard about getting kicked in the face, and there will be no wall to push off and get that extra second of rest. also,  i figure i will have to train a bit with my head out of the water so i can have a look around from time to time.  

with that said, i think i am happy with that beginning time especially since this is second time in the pool in about 2 years (first time was about 2 weeks ago).  if i come out of the swim in the middle of the pack i will be happy.  this is my first race after all, i want to finish and have fun! 

You have all summer to get the hang of the swim again.  I'm assuming you swam quite a bit faster back in 9th grade.  It's always easier to regain your form than to find it in the first place.

So I am sure that your goal time is easily available to you if you stick to your plan of 2 swim workouts per week.

15 min is very doable. 

the thing with swimming is if you got the stroke hard-wired already, all you have to work on is fitness and endurance...2 times a week (with solid workouts each time) is enough to get you through the race in a good time. 

now if you want to get a top top time, you probably would need to do 3-4/week with pretty structured workouts, but you would then need to take a look at your bike and run and see if those need more work.  

Also, a strong core section (abs and lower back) really helps with swimming ability especially speed, so if you include ab workout a few times a week...you are golden. 

FYI, if it's an open water swim, your time will be largely dependant on how well the course is set up.

I just did a sprint with a 750m ocean swim.  I watched the lifeguards set up the bouys...they pretty much just paddled out and dropped anchor where they felt like it.  They didn't have anyone on shore directing them, and I know they weren't using a gps.

I did the swim in under 11 minutes...there is no way I'm that fast.  Fastest guy out of the water did it 7:18 (or roughly 53 seconds per 100y).  Last year, the same guy did the swim (marked differently) but still advertised as 750m in 10:41.  He's been pro level for several years, so it's highly unlikely his improvements were due to fitness gains.