Protected Waters
If initial seasteading were done in protected waters the engineering of the structures would be easier and the costs would be lower. So there are advantages to starting out where the waves are not too big. This is one of the seastead startup strategies. It allows for a more incremental approach than going directly for open ocean with big waves.
There are protected waters with International waters. For example the Baltic and maybe Mediterranean.
It might also be reasonable to start Floating Villas off a taxhaven like Anguilla with the intent to move further and further out over time.