Nitpicking: Switzerland actually does have three ports that provide, protected by international law, access to the North Sea (via the Rhine) and the Black Sea (via the Rhine–Main–Danube canal). In terms of quantities, about 10% of imports are going through these ports, mainly bulk load.
Source (only in german): https://de.wikipedia.org/wiki/Schweizerische_Rheinh%C3%A4fen