Melco tape is the usual choice for this It's a three layer tape with an outer nylon layer which comes in several colors, and is extremely stretch, so it works on high flex divesuit materials (if you use a non-stretchy tape on a stretchy material you can end up putting more stress on the seems). McNett packages it, though you can get it from some outdoor fabric vendors cheaper.
There's also a thinner version that is almost transparent and doesn't have the nylon layer, which is more suitable for inside use, but has been much harder to find in small quantity. This is what the Sympatex appears to be.