Nordic countries formed the Nordic Council due to shared history and culture. While this was happening Estonia was unfortunately occupied by the USSR.
We believe that Estonia (also known as Estland) would have been a natural, undisputed part the Nordic countries had it not lost its independence in WW2. Iron Curtain caused much of Estonia’s nordic-like history to become unknown in the West.
We look past the 40+ years of Soviet occupation and see a thousand+ years of shared history between the Finnic people (Estonians & Finns) and the Germanic. Sea is often seen as a physical divider, but instead it’s a connector, culture has always thrived on coastal areas and sea-routes have been the main way how culture and traditions spread.