1/2 marathon to Sprint Tri 's to Full Marathon

heres an option,   if your worried about overdoing your legs since the 1/2 marathon is your focus THEN i would tack in 2-3 swim workouts per week now.  Your legs will be focused on the 1/2 marathon BUT you can get your swimming ready for the sprints in june/july no problem...just so you have a day of rest minimum per week.  keep the swim on the conservative side...make them 'easier' workouts...save most for your running.  Bring the cycling in after your 1/2 marathon...3-4months should be plenty of time to build up some cycling for a sprint.

Hey I am in somewhat the same boat. I have my first 1/2 marathon in May. Then my first sprint tri is 4 weeks later. I wasn't sure how I could do both in such a short time. However I found out that the mini-marathon has a virtual coach and we are able to ask a coach questions via email. She is a coach with Chicago Endurance Sports and co-author of marathoning for mortals, I asked her about this very situation and she gave me a workout schedule for working up to the race. I told her my focus is the triathlon and the mini marathon I was treating more as a long workout. The schedule included two days for cross-training built in.

My situation is also different since I will only have 4 weeks to recover/prepare for my first tri. I will probably double up some days with a swim workout on the same day as a run or bike to get a mix of 3 swim days or 3 bike days in while the other disipline is on a 2 day week and keep my running to 3-4 days depending on her schedule.

I also think it depends on where you are with your base building phase. It sounds like you are doing well in that area and if you are you can definately add in a swim and/or bike depending on what you need to work on the most. Unfortunately for me it is kind of both but definately the swim needs work.

I"m currently training for my first marathon - end of March. But my main focus is the summer tri season starting in mid May. So pretty similar to you. The marathon program that I'm following has 2 recovery run days in it. The Author mentioned that these were droppable if replaced by crosstraining. So that's what I'm doing. I'm swimming 2 times a week and doing weights 2 times. I'm only cycling 1-2 times a week and just spinning easy for recovery. I'm not too worried about the bike since this is my strongest event. I usually do weights and swim on the same day - am/pm. Anyway just set your priorities and do what feels right.

When I trained for my half marathon, I used Galloway's program and only ran 3 days a week. I then cross trained 3 days a week with Ultimate Frisbee and cycling. I have since found that cycling at a higher cadence (try to get to 90) will also help your running without the pounding. So try to incorporate the other sports in as able.