There is no such thing as the "Baltic Peninsula". If you mean the Balkan Peninsula, it is made up of 11 countries:
Norway and Sweden
Norway and Sweden
Sweden and Norway
Scandinavia
The Baltic Sea does not border any one continent from another. It is a body of water that is surrounded by European countries.
the Scandinavian peninsula
Scandinavian peninsula
The Baltic Sea is bordered by the continents of Europe to the south and Asia to the east. The countries with coastlines along the Baltic Sea include Sweden, Finland, Estonia, Latvia, Lithuania, Poland, Germany, and Denmark.
The Scandinavian Peninsula is a peninsula in Northern Europe. It includes the countries of Norway and Sweden as well as parts of Finland.
Southeast
The three Baltic republics are called the Baltic states, Baltics, Baltic nations, or Baltic countries. The countries include Lithuania, Latvia, Estonia.
The three Baltic republics are Latvia, Lithuania, and Estonia