Dolfin fit is very similar to Speedo. My experience with TYR is that it runs small. These are for men's briefs.

Today I got got my order or two different swim briefs. I ordered a black speedo brief and a red Nike brief both in size 30. After trying them both on, I like the fit of the Nike better, but the feel of the speedo. They both are a little tight, but I hope to stray getting back in shape to make them fit better.

New suits will fit quite snug at first. As you wear them they will gradually conform to your body like a favorite pair of jeans often do over time.