Hi,
there really is no strict dress code on the NCL Freestyle Cruising ships. "Smart casual" might be a good term for what is often found. This means no jeans, no t-shirts etc., but e.g. slacks and a nice shirt are perfectly fine. If you would like to dress up, no problem. There will be at least one formal night in one of the restaurants. If don't care about that, no problem either.
Best regards,
Raoul Fiebig
Das Ruderhaus