Dizzy after a swim, what am I doing wrong?

I find it to happen a lot too. I think it mainly depends on the person. Being horizontal and turning your head to the side a bunch makes me dizzy everytime when I hop upright. I get super dizzy but my fiance doesnt. And we would swim ALOT. I dont know.. maybe its just me that thinks that its completely normal.

I had the same problem the first few times I started training for a Tri.

To get somewhat used to the feeling, I would "run" a lap in the pool after my laps to try to keep my balance.  From there, I moved up to fast walking over to the water fountain, and a few days later a fast walk to the water fountain and to the locker room.

It's just getting used to it.  A few practices and you'll be fine.

Are you getting enough air in?  If you're not training much - you might be gasping/holding your breath/etc. while swimming and that will also contribute to lightheadedness.

Unfortunately, I think to fix your problem, you need to be in the water more.  I was a competitive swimmer, and even after taking a month or so off between seasons, I had to "start over" with some of the adjustments.  Getting enough air is important too (so working on your breathing), but just getting used to being horizontal in the water and then standing up is an adjustment to your system.  I think you'd probably be OK with some time in the water.

I do plan on getting in the pool more. I kind of rushed in to my first 2 sprint tri's (they were 2 weeks apart) just so I could get a race or two in before the end of the season. Over the winter I plan on spending a lot of time in the pool so I'm glad to hear that this is something that will get (hopefully) better with some training.

x2 on the earplugs.  I used to nearly fall over after every pool workout.  It would take me a couple minutes to feel normal again...not so great when you have to balance yourself on a bike!  After getting the earplugs tip from BT I've never had any issues.  Kind of a pain to have one more thing to keep track of at a race, but well worth it.

I have also had very good luck with swimming the last 100 yards or so kicking hard, much harder than 'efficient' to get more blood flowing in your legs before you stand up.  Most people get dizzy because there is less blood in their legs, and when they stand up it rushes back down and away from your head giving you the light headed feeling.

I'm a lifelong swimmer and it happened to me today.  I also, think it's completely normal.  It should pass quickly, though, I think.  if it's lasting longer than T1 - I'd ask someone with medical knowledge about it.

good luck