Swimming making me gain?

Swimming is great however like most exercise it has a tendency to increase your appetite so you need to make sure you are not increasing your portions to a size which more than makes up for the calories you are using in the pool.

If you measure and track for a few weeks you will be able to work out if it is that case.

Definitely have a look at your food. I swim a lot and have been steadily losing weight. I also go to aquafit twice a week (and swim 500 m before my class) and I try to walk 40-60 minutes a day. I tend to be a morning swimmer and do find that I am hungry afterwards, but I usually fend that off with a banana or something. Swimming burns a lot of calories and can help with muscle building due to resistance. There's no reason you should be gaining weight if your calorie intake is correct unless there is some underlying medical condition.

So, an hour 2-3 times a week is only burning 1200-1800 calories a week, and that's freestyle which includes front and back stroke. If you are not doing these two strokes and are just doing breast stroke or flutter board, you are definitely burning less than 1200-1800 calories. You could easily cancel that out by just overeating a little every day. I suggest you add more to your exercise routine and focus on your swim stroke efficiency. Get a coach to help you figure that out.

Agree with the posts above. Most of my weight has come off from swimming. Right now, I'm in the pool at least 2 times per week for an hour, swimming in all 4 race strokes. When I first started swimming I wasn't able to do the butterfly, so I subbed side stroke for this one. I'm finishing approximately 1600 m in that time.

I also lift 2 or 3 days per week.

I'm not positive my actual burns, though with the calculators I've found (NOT MFP) I tend to burn between 700 (lifting days) - 1800 (Swim days). Starting in May, because I got tired of seeing 3000 - 4000 calorie goals that I Just flat couldn't eat enough to hit, I switched to the TDEE-% calculation, and so do not have to worry quite so much about the actual exercise burns. The loss has been pretty steady, averaging 1.5 pounds + per week, though recently things have slowed down a little, which I am attributing to my body rearranging things for further loss. (I haven't lost much, and actually put ON inches, while getting jigglier)

Logging everything is definitely key to a consistent loss on the scales. And finding out when is the best time for you to swim. I've tried bright and early, right out of bed, and I've swam at the end of the day or in the middle. At almost any time I swim, if I haven't eaten about an hour before I swim, I find my appetite uncontrolled when I get out.