It really depends on where you're getting them from. In our experience, one pieces usually run a size small and 2 pieces usually run tts. We do have a one piece from Gymboree that seems to run pretty tts, though.
Last summer when DD was 18/24/2T we got her a one piece in a 3T and really could have done a 4T!!! That's how small in ran.
I remember a few suits from last summer that seemed to run very small on my daughter. They were from Target and Kmart. I would think 2 pieces would fit more true to size. The one pieces seemed to be snug on my girl.
Usually I buy one size bigger in a one piece. DD is so darn skinny that I can't buy her two pieces, the bottoms fall off especially with no swim diapers.
Well I can only speak for Gymboree. I just bought my dd 2 different 2 piece suits from there with the sunguard and she is starting to go into 3t but the 3t was wayy too big and since she no longer wears a diaper the 2t on the bottom was big around the legs. So Gymboree runs big.
It depends on where they're from. Gymboree I always buy her size, most other places including ON, Gap, and Target I always buy one, sometimes even two sizes up.
Re: Do bathing suits run true to size for your DD?
It really depends on where you're getting them from. In our experience, one pieces usually run a size small and 2 pieces usually run tts. We do have a one piece from Gymboree that seems to run pretty tts, though.
Last summer when DD was 18/24/2T we got her a one piece in a 3T and really could have done a 4T!!! That's how small in ran.
Not even close. Neither of my girls can do one pieces bc they are both sooo long waisted.
And with 2 pieces, they are both normal on top, but have very narrow, petite hips. Sounds about the same as your DD. I go up a size.